diff --git a/CDC1700/CDC1700-MSOS.txt b/CDC1700/CDC1700-MSOS.txt
index 386fa304..d800f49e 100644
--- a/CDC1700/CDC1700-MSOS.txt
+++ b/CDC1700/CDC1700-MSOS.txt
@@ -46,8 +46,8 @@ Sample installation run of MSOS 5 (user input to MSOS is marked with "<==="):
         sim> set lp type=1742
         sim> att lp MSOSinstall.lpt
         LP: creating new file
-        sim> att cd0 MSOS5.dsk
-        CD: creating new file
+        sim> att cdd0 MSOS5.dsk
+        CDD: creating new file
         sim> boot mt0
 
         MSOS 5.0 SYSTEM INITIALIZER 
@@ -548,7 +548,7 @@ Sample installation run of MSOS 5 (user input to MSOS is marked with "<==="):
           POWERU
           INITIALIZATION COMPLETED - YOU MAY AUTOLOAD 
         Simulation stopped, P: 5914 (  18FF                    JMP*    $FF)
-        sim> autoload cd
+        sim> autoload cdd
         sim> run 0
 
 
diff --git a/CDC1700/CDC1700.txt b/CDC1700/CDC1700.txt
index 6af4551e..711d1ce7 100644
--- a/CDC1700/CDC1700.txt
+++ b/CDC1700/CDC1700.txt
@@ -14,8 +14,9 @@ mostly from the early period of its release:
 
         device name     Hardware
 
-        CPU             1714 CPU with up to 32KW of memory in 4KW increments
-                        1705 Interrupt/Data channel option
+        CPU             1714 CPU with 4KW, 8KW, 16KW or 32KW of memory
+                        1705 Multi-Level Interrupt and Direct Storage Access
+                        Bus
 
                         Optional extensions:
 
@@ -70,7 +71,7 @@ mostly from the early period of its release:
 
                         [Equipment address: 0x3]
 
-        CD              1733-2 Cartridge disk pack controller. Supports up to
+        CDD             1733-2 Cartridge disk pack controller. Supports up to
                         4 cartridge disk drives. Each drive supports a fixed
                         and a removeable disk:
 
@@ -80,13 +81,13 @@ mostly from the early period of its release:
                         [Equipment address: 0x3]
 
 Notes:
-        DP and CD use the same equipment address so only 1 of them may be
-        enabled (default is for CD to be enabled).
+        DP and CDD use the same equipment address so only 1 of them may be
+        enabled (default is for CDD to be enabled).
 
         Both controllers use checkwords (CRC) for validating the consistency
         of the data stored on disk. The DP controller exports a single status
         bit indicating whether the checkword is valid or not (the simulator
-        always sets this to valid). The CD controller also exports a single
+        always sets this to valid). The CDD controller also exports a single
         status bit  which is handled in the same way as the DP controller.
         It also makes the actual checkword value available. The simulator
         always returns a checkword value of 0 so any attempt to verify the
diff --git a/CDC1700/cdc1700_cd.c b/CDC1700/cdc1700_cd.c
index cf3e92bb..6abad9c0 100644
--- a/CDC1700/cdc1700_cd.c
+++ b/CDC1700/cdc1700_cd.c
@@ -51,7 +51,6 @@ extern void rebuildPending(void);
 
 extern t_stat checkReset(DEVICE *, uint8);
 
-extern t_stat show_debug(FILE *, UNIT *, int32, CONST void *);
 extern t_stat show_addr(FILE *, UNIT *, int32, CONST void *);
 
 extern t_stat set_protected(UNIT *, int32, CONST char *, void *);
@@ -83,6 +82,8 @@ static t_stat show_addressing(FILE *, UNIT *, int32, CONST void *);
 t_stat set_cartfirst(UNIT *, int32, CONST char *, void *);
 t_stat set_fixedfirst(UNIT *, int32, CONST char *, void *);
 
+t_stat cd_help(FILE *, DEVICE *, UNIT *, int32, const char *);
+
 /* Constants */
 
 #define CD_NUMWD        (96)            /* words/sector */
@@ -351,53 +352,61 @@ UNIT cd_unit[] = {
 };
 
 REG cd_reg[] = {
-  { HRDATA(FUNCTION, CDdev.FUNCTION, 16) },
-  { HRDATA(STATUS, CDdev.STATUS, 16) },
-  { HRDATA(IENABLE, CDdev.IENABLE, 16) },
+  { HRDATAD(FUNCTION, CDdev.FUNCTION, 16, "Last director function issued") },
+  { HRDATAD(STATUS, CDdev.STATUS, 16, "Director status register") },
+  { HRDATAD(IENABLE, CDdev.IENABLE, 16, "Interrupts enabled") },
   /*** more ***/
   { NULL }
 };
 
 MTAB cd_mod[] = {
-  { MTAB_XTD|MTAB_VDV, 0, "1733-2", NULL, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", NULL, NULL, &show_addr, NULL },
-  { MTAB_XTD|MTAB_VDV|MTAB_VALR, 0, NULL, "EQUIPMENT", &set_equipment, NULL, NULL },
-  { MTAB_XTD|MTAB_VUN, 0, "DRIVE", NULL, NULL, &show_drive, NULL },
-  { MTAB_XTD|MTAB_VUN, 0, NULL, "856-2", &set_cd856_2, NULL, NULL },
-  { MTAB_XTD|MTAB_VUN, 0, NULL, "856-4", &set_cd856_4, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "DEBUG", NULL, NULL, &show_debug, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "STOPONREJECT", &set_stoponrej, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOSTOPONREJECT", &clr_stoponrej, NULL, NULL },
+  { MTAB_XTD|MTAB_VDV, 0, "1733-2 Cartridge Disk Drive Controller" },
+  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", "EQUIPMENT=hexAddress",
+    &set_equipment, &show_addr, NULL, "Display equipment address" },
+  { MTAB_XTD|MTAB_VUN, 0, "DRIVE", NULL,
+    NULL, &show_drive, NULL, "Display type of drive (856-2 or 856-4)" },
+  { MTAB_XTD|MTAB_VUN, 0, NULL, "856-2",
+    &set_cd856_2, NULL, NULL, "Set drive type to 856-2" },
+  { MTAB_XTD|MTAB_VUN, 0, NULL, "856-4",
+    &set_cd856_4, NULL, NULL, "Set drive type to 856-4" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "STOPONREJECT",
+    &set_stoponrej, NULL, NULL, "Stop simulation if I/O is rejected" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOSTOPONREJECT",
+    &clr_stoponrej, NULL, NULL, "Don't stop simulation if I/O is rejected" },
   /*** should protect be per-unit? ***/
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "PROTECT", &set_protected, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT", &clear_protected, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "ADDRESSING", NULL, NULL, &show_addressing, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "CARTFIRST", &set_cartfirst, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "FIXEDFIRST", &set_fixedfirst, NULL, NULL },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "PROTECT",
+    &set_protected, NULL, NULL, "Device is protected (unimplemented)" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT",
+    &clear_protected, NULL, NULL, "Device is unprotected (unimplemented)"  },
+  { MTAB_XTD|MTAB_VDV, 0, "ADDRESSING", NULL,
+    NULL, &show_addressing, NULL, "Show disk addressing mode" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "CARTFIRST",
+    &set_cartfirst, NULL, NULL, "Set cartridge as logical disk 0" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "FIXEDFIRST",
+    &set_fixedfirst, NULL, NULL, "Set fixec disk as logical disk 0" },
   { 0 }
 };
 
 DEBTAB cd_deb[] = {
-  { "TRACE", DBG_DTRACE },
-  { "STATE", DBG_DSTATE },
-  { "INTR", DBG_DINTR },
-  { "ERROR", DBG_DERROR },
-  { "LOCATION", DBG_DLOC },
-  { "FIRSTREJ", DBG_DFIRSTREJ },
+  { "TRACE",       DBG_DTRACE,     "Trace device I/O requests" },
+  { "STATE",       DBG_DSTATE,     "Display device state changes" },
+  { "INTR",        DBG_DINTR,      "Display device interrupt requests" },
+  { "ERROR",       DBG_DERROR,     "Display device errors" },
+  { "LOCATION",    DBG_DLOC,       "Display address for I/O instructions" },
+  { "FIRSTREJ",    DBG_DFIRSTREJ,  "Suppress display of 2nd ... I/O rejects" },
   { "ALL", DBG_DTRACE | DBG_DSTATE | DBG_DINTR | DBG_DERROR | DBG_DLOC },
   { NULL }
 };
 
 DEVICE cd_dev = {
-  "CD", cd_unit, cd_reg, cd_mod,
+  "CDD", cd_unit, cd_reg, cd_mod,
   CD_NUMDR * 2, 10, 31, 1, 8, 8,
   NULL, NULL, &cd_reset,
   NULL, &cd_attach, &cd_detach,
   &CDdev,
   DEV_DEBUG | DEV_DISK | DEV_DISABLE | DEV_INDEV | DEV_OUTDEV | DEV_PROTECT,
   0, cd_deb,
-  NULL,
-  NULL
+  NULL, NULL, &cd_help, NULL, NULL, NULL
 };
 
 /*
@@ -1325,3 +1334,41 @@ t_stat CDautoload(void)
   }
   return SCPE_UNATT;
 }
+
+t_stat cd_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
+{
+  const char helpString[] =
+    /****************************************************************************/
+    " The %D device is a 1733-2 cartridge disk drive controller.\n"
+    "1 Hardware Description\n"
+    " The 1733-2 consists of a controller with up to 4 attached disk drives.\n"
+    " Each drive consists of 2 logical disks; a removeable disk pack and a\n"
+    " fixed disk. The controller includes a jumper which controls which disk\n"
+    " is addressed as logical disk 0:\n\n"
+    "+sim> SET %D CARTFIRST\n"
+    "+sim> SET %D FIXEDFIRST\n\n"
+    " Each physical drive may be configured as a 856-2 or 856-4 and both the\n"
+    " fixed and removeable disks must be the same size.\n\n"
+    "+856-2 drive: 1130304 words per disk\n"
+    "+856-4 drive: 2271744 words per disk\n\n"
+    " The configuration may be changed by referencing either of the logical\n"
+    " disks present on a drive:\n\n"
+    "+sim> SET %U 856-2\n"
+    "+sim> SET %U 856-4\n\n"
+    "2 Equipment Address\n"
+    " Disk controllers are typically set to equipment address 3. This address\n"
+    " may be changed by:\n\n"
+    "+sim> SET %D EQUIPMENT=hexValue\n\n"
+    "2 $Registers\n"
+    "\n"
+    " These registers contain the emulated state of the device. These values\n"
+    " don't necessarily relate to any detail of the original device being\n"
+    " emulated but are merely internal details of the emulation. STATUS always\n"
+    " contains the current status of the device as it would be read by an\n"
+    " application program.\n"
+    "1 Configuration\n"
+    " A %D device is configured with various simh SET and ATTACH commands\n"
+    "2 $Set commands\n";
+
+  return scp_help(st, dptr, uptr, flag, helpString, cptr);
+}
diff --git a/CDC1700/cdc1700_cpu.c b/CDC1700/cdc1700_cpu.c
index 3ae42e25..c7c16825 100644
--- a/CDC1700/cdc1700_cpu.c
+++ b/CDC1700/cdc1700_cpu.c
@@ -83,7 +83,7 @@ uint8 P[MAXMEMSIZE];
 
 t_uint64 Instructions;
 uint16 Preg, Areg, Qreg, Mreg, CAenable, OrigPreg, Pending, IOAreg, IOQreg;
-uint8 Pfault, Protected, lastP, Oflag, PARflag, INTflag, DEFERflag;
+uint8 Pfault, Protected, lastP, Oflag, INTflag, DEFERflag;
 
 t_bool ExecutionStarted = FALSE;
 uint16 CharAddrMode[16];
@@ -110,6 +110,8 @@ t_stat cpu_set_size(UNIT *, int32, CONST char *, void *);
 t_stat cpu_ex(t_value *, t_addr, UNIT *, int32);
 t_stat cpu_dep(t_value, t_addr, UNIT *uptr, int32 sw);
 
+t_stat cpu_help(FILE *, DEVICE *, UNIT *, int32, const char *);
+
 #define UNIT_V_STOPSW   (UNIT_V_UF + 1)         /* Selective STOP switch */
 #define UNIT_STOPSW     (1 << UNIT_V_STOPSW)
 #define UNIT_V_SKIPSW   (UNIT_V_UF + 2)         /* Selective SKIP switch */
@@ -123,7 +125,7 @@ t_stat cpu_dep(t_value, t_addr, UNIT *uptr, int32 sw);
 #define UNIT_V_MSIZE    (UNIT_V_UF + 6)         /* Memory size */
 #define UNIT_MSIZE      (1 << UNIT_V_MSIZE)
 
-IO_DEVICE CPUdev = IODEV(NULL, "1704", CPU, 0, 0xFF, 0,
+IO_DEVICE CPUdev = IODEV(NULL, "1714", CPU, 0, 0xFF, 0,
                          NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
                          0, 0, 0, 0, 0, 0, 0, 0, NULL);
 
@@ -137,39 +139,53 @@ IO_DEVICE CPUdev = IODEV(NULL, "1704", CPU, 0, 0xFF, 0,
 UNIT cpu_unit = { UDATA(NULL, UNIT_FIX+UNIT_BINK, DEFAULTMEMSIZE) };
 
 REG cpu_reg[] = {
-  { HRDATA(P, Preg, 16) },
-  { HRDATA(A, Areg, 16) },
-  { HRDATA(Q, Qreg, 16) },
-  { HRDATA(M, Mreg, 16) },
-  { HRDATA(O, Oflag, 1) },
-  { HRDATA(CH, CAenable, 1) },
-  { HRDATA(PAR, PARflag, 1) },
-  { HRDATA(INT, INTflag, 1) },
-  { HRDATA(DEFER, DEFERflag, 1) },
-  { HRDATA(PENDING, Pending, 1) },
-  { HRDATA(PFAULT, Pfault, 1) },
+  { HRDATAD(P, Preg, 16, "Program address counter") },
+  { HRDATAD(A, Areg, 16, "Principal arithmetic register") },
+  { HRDATAD(Q, Qreg, 16, "Index register") },
+  { HRDATAD(M, Mreg, 16, "Interrupt mask register") },
+  { HRDATAD(O, Oflag, 1, "Overflow flag") },
+  { HRDATAD(CH, CAenable, 1, "Character addressing enable flag") },
+  { HRDATAD(INT, INTflag, 1, "Interrupt enable flag") },
+  { HRDATAD(DEFER, DEFERflag, 1, "Interrupt deferred flag") },
+  { HRDATAD(PENDING, Pending, 16, "Pending interrupt flags") },
+  { HRDATAD(PFAULT, Pfault, 1, "Protect fault pending flag") },
   { NULL }
 };
 
 MTAB cpu_mod[] = {
-  { UNIT_STOPSW, UNIT_STOPSW, "Selective Stop", "SSTOP", NULL },
-  { UNIT_STOPSW, 0, "No Selective Stop", "NOSSTOP", NULL },
-  { UNIT_SKIPSW, UNIT_SKIPSW, "Selective Skip", "SSKIP", NULL },
-  { UNIT_SKIPSW, 0, "No Selective Skip", "NOSSKIP", NULL },
-  { UNIT_MODE65K, UNIT_MODE65K, "65K Addressing Mode", "MODE65K", NULL },
-  { UNIT_MODE65K, 0, "32K Addressing Mode", "MODE32K", NULL },
-  { UNIT_CHAR, UNIT_CHAR, "Character Addressing", "CHAR", NULL },
-  { UNIT_CHAR, 0, "No Character Addressing", "NOCHAR", NULL },
-  { UNIT_PROT, UNIT_PROT, "Program Protect", "PROTECT", NULL },
-  { UNIT_PROT, 0, "", "NOPROTECT", NULL },
-  { UNIT_MSIZE, 4096, NULL, "4K", &cpu_set_size },
-  { UNIT_MSIZE, 8192, NULL, "8K", &cpu_set_size },
-  { UNIT_MSIZE, 16384, NULL, "16K", &cpu_set_size },
-  { UNIT_MSIZE, 32768, NULL, "32K", &cpu_set_size },
+  { MTAB_XTD|MTAB_VDV, 0, "1714 CDC 1700 series CPU", NULL, NULL, NULL },
+  { UNIT_STOPSW, UNIT_STOPSW, "Selective Stop", "SSTOP",
+    NULL, NULL, NULL, "Enable Selective Stop" },
+  { UNIT_STOPSW, 0, "No Selective Stop", "NOSSTOP",
+    NULL, NULL, NULL, "Disable Selective Stop" },
+  { UNIT_SKIPSW, UNIT_SKIPSW, "Selective Skip", "SSKIP",
+    NULL, NULL, NULL, "Enable Selective Skip" },
+  { UNIT_SKIPSW, 0, "No Selective Skip", "NOSSKIP",
+    NULL, NULL, NULL, "Disable Selective Skip" },
+  { UNIT_MODE65K, UNIT_MODE65K, "65K Addressing Mode", "MODE65K",
+    NULL, NULL, NULL, "Enable 65K Indirect Addressing Mode" },
+  { UNIT_MODE65K, 0, "32K Addressing Mode", "MODE32K",
+    NULL, NULL, NULL, "Enable 32K Indirect Addressing Mode" },
+  { UNIT_CHAR, UNIT_CHAR, "Character Addressing", "CHAR",
+    NULL, NULL, NULL, "Enable Character Addressing Mode" },
+  { UNIT_CHAR, 0, "No Character Addressing", "NOCHAR",
+    NULL, NULL, NULL, "Disable Character Addressing Mode" },
+  { UNIT_PROT, UNIT_PROT, "Program Protect", "PROTECT",
+    NULL, NULL, NULL, "Enable Protect Mode Operation" },
+  { UNIT_PROT, 0, "", "NOPROTECT",
+    NULL, NULL, NULL, "Disable Protect Mode Operation" },
+  { UNIT_MSIZE, 4096, NULL, "4K",
+    &cpu_set_size, NULL, NULL, "Set Memory Size to 4KW" },
+  { UNIT_MSIZE, 8192, NULL, "8K",
+    &cpu_set_size, NULL, NULL, "Set Memory Size to 8KW" },
+  { UNIT_MSIZE, 16384, NULL, "16K",
+    &cpu_set_size, NULL, NULL, "Set Memory Size to 16KW" },
+  { UNIT_MSIZE, 32768, NULL, "32K",
+    &cpu_set_size, NULL, NULL, "Set Memory Size to 32KW" },
 #if MAXMEMSIZE > 32768
-  { UNIT_MSIZE, 65536, NULL, "64K", &cpu_set_size },
+  { UNIT_MSIZE, 65536, NULL, "64K",
+    &cpu_set_size, NULL, NULL, "Set Memory Size to 64KW" },
 #endif
-  { MTAB_XTD | MTAB_VDV, 0, "1714", NULL, NULL, NULL },
   { 0 }
 };
 
@@ -177,18 +193,18 @@ MTAB cpu_mod[] = {
   (DBG_DISASS | DBG_TRACE | DBG_TARGET | DBG_INPUT | DBG_OUTPUT | DBG_FULL)
 
 DEBTAB cpu_deb[] = {
-  { "DISASSEMBLE", DBG_DISASS },
-  { "IDISASSEMBLE", DBG_IDISASS },
-  { "INTERRUPT", DBG_INTR },
-  { "TRACE", DBG_TRACE },
-  { "ITRACE", DBG_ITRACE },
-  { "TARGET", DBG_TARGET },
-  { "INPUT", DBG_INPUT },
-  { "OUTPUT", DBG_OUTPUT },
-  { "IO", DBG_INPUT | DBG_OUTPUT },
-  { "INTLVL", DBG_INTLVL },
-  { "PROTECT", DBG_PROTECT },
-  { "MISSING", DBG_MISSING },
+  { "DISASSEMBLE",  DBG_DISASS,    "Disassemble instructions while tracing" },
+  { "IDISASSEMBLE", DBG_IDISASS,   "Disassemble while interrupts active" },
+  { "INTERRUPT",    DBG_INTR,      "Display interrupt entry/exit" },
+  { "TRACE",        DBG_TRACE,     "Trace instruction execution" },
+  { "ITRACE",       DBG_ITRACE,    "Trace while interrupts active" },
+  { "TARGET",       DBG_TARGET,    "Display target address of instructions" },
+  { "INPUT",        DBG_INPUT,     "Display INP instruction execution" },
+  { "OUTPUT",       DBG_OUTPUT,    "Display OUT instruction execution" },
+  { "IO",           DBG_INPUT | DBG_OUTPUT, "Display INP and OUT execution" },
+  { "INTLVL",       DBG_INTLVL,    "Add interrupt level to all displays" },
+  { "PROTECT",      DBG_PROTECT,   "Display protect faults" },
+  { "MISSING",      DBG_MISSING,   "Display info about missing devices" },
   { "FULL", DBG_ALL },
   { NULL }
 };
@@ -200,8 +216,7 @@ DEVICE cpu_dev = {
   NULL, NULL, NULL,
   &CPUdev,
   DEV_DEBUG | DEV_NOEQUIP, 0, cpu_deb,
-  NULL,
-  NULL
+  NULL, NULL, &cpu_help, NULL, NULL, NULL
 };
 
 /*
@@ -1546,3 +1561,76 @@ t_stat sim_instr(void)
   }
   return reason;
 }
+
+t_stat cpu_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
+{
+  const char helpString[] =
+    /****************************************************************************/
+    " The %D device is a 1714 central processing unit.\n"
+    "1 Hardware Description\n"
+    " The 1714 can access up to 64KW of memory (4KW, 8KW, 16KW, 32KW and 64KW\n"
+    " are supported). A 1705 multi-level interrupt system with a direct\n"
+    " storage access bus and 3 1706-A buffered data channels are included.\n\n"
+    " The amount of memory available to the system can be changed with:\n\n"
+    "+sim> SET CPU nK\n\n"
+    " The original 1700 series CPU (the 1704) only allowed up to 32KW to be\n"
+    " attached to the CPU and indirect memory references would continue to\n"
+    " loop through memory if bit 15 of the target address was set. When 64KW\n"
+    " support was added indirect addressing was limited to a single level\n"
+    " so that the entire 16-bits of address could be used. The indirect\n"
+    " addressing mode may be changed by:\n\n"
+    "+sim> SET CPU MODE32K\n"
+    "+sim> SET CPU MODE65K\n\n"
+    " In 32KW addressing mode, the number of indirect address chaining\n"
+    " operations is limited to 10000 to avoid infinite loops.\n"
+    "2 Equipment Address\n"
+    " The CPU is not directly accessible via an equipment address but it does\n"
+    " reserve interrupt 0  (and therefore equipment address 0) for parity\n"
+    " errors (never detected by the simulator), protect faults and power fail\n"
+    " (not supported by the simulator).\n"
+    "2 $Registers\n"
+    "2 Front Panel Switches\n"
+    " The 1714 front panel includes a number of switches which control the\n"
+    " operation of the CPU. Note that selective stop and selective skip are\n"
+    " used extensively to control execution of the System Maintenance\n"
+    " Monitor.\n"
+    "3 Selective Stop\n"
+    " The selective stop switch controls how the 'Selective Stop' (SLS)\n"
+    " instruction executes. If the switch is off, SLS executes as a\n"
+    " no-operation. If the switch is on, SLS executes as a halt instruction.\n"
+    " Continuing after the halt causes the CPU to resume execution at the\n"
+    " instruction following the SLS.\n\n"
+    "+sim> SET CPU SSTOP\n"
+    "+sim> SET CPU NOSSTOP\n\n"
+    "3 Selective Skip\n"
+    " The selective skip switch controls how the SWS and SWN skip\n"
+    " instructions execute. SWS will skip if the switch is set and SWN will\n"
+    " skip if the switch is not set.\n\n"
+    "+sim> SET CPU SSKIP\n"
+    "+sim> SET CPU NOSSKIP\n\n"
+    "3 Protect\n"
+    " Each word of memory on the CDC 1700 series consists of 18-bits; 16-bits\n"
+    " of data/instruction, a parity bit (which is not implemented in the\n"
+    " simulator) and a program bit. If the protect switch is off, any program\n"
+    " may reference any word of memory. If the protect switch is on, there are\n"
+    " a set of rules which control how memory accesses work and when to\n"
+    " generate a program protect violation - see one of the 1700 reference\n"
+    " manuals on bitsavers.org for exact details. This means that the\n"
+    " operating system can be protected from modification by application\n"
+    " programs but there is no isolation between application programs.\n\n"
+    "+sim> SET CPU PROTECT\n"
+    "+sim> SET CPU NOPROTECT\n\n"
+    " The Simulator fully implements CPU protect mode allowing protected\n"
+    " operating systems such as MSOS 5 to execute. It does not implement\n"
+    " peripheral protect operation which allows unprotected applications to\n"
+    " directly access some unprotected peripherals.\n\n"
+    " Operating systems and other programs which run with the protect switch\n"
+    " on usually start up with the protect switch off, manipulate the\n"
+    " protect bits in memory (using the CPB/SPB instructions) and then ask\n"
+    " the operator to set the protect switch on.\n"
+    "1 Configuration\n"
+    " The CPU is configured with various simh SET commands.\n"
+    "2 $Set commands\n";
+
+  return scp_help(st, dptr, uptr, flag, helpString, cptr);
+}
diff --git a/CDC1700/cdc1700_dc.c b/CDC1700/cdc1700_dc.c
index 332b08cd..9ce4ddf5 100644
--- a/CDC1700/cdc1700_dc.c
+++ b/CDC1700/cdc1700_dc.c
@@ -53,8 +53,6 @@ extern enum IOstatus fw_doBDCIO(IO_DEVICE *, uint16 *, t_bool, uint8);
 extern uint16 LoadFromMem(uint16);
 extern t_bool IOStoreToMem(uint16, uint16, t_bool);
 
-extern t_stat show_debug(FILE *, UNIT *, int32, CONST void *);
-
 t_stat set_intr(UNIT *uptr, int32 val, CONST char *, void *);
 t_stat show_intr(FILE *, UNIT *, int32, CONST void *);
 t_stat show_target(FILE *, UNIT *, int32, CONST void *);
@@ -67,6 +65,8 @@ t_bool DCreject(IO_DEVICE *, t_bool, uint8);
 enum IOstatus DCin(IO_DEVICE *, uint8);
 enum IOstatus DCout(IO_DEVICE *, uint8);
 
+t_stat dc_help(FILE *, DEVICE *, UNIT *, int32, const char *);
+
 /*
         1706-A Buffered Data Channel
 
@@ -203,46 +203,46 @@ UNIT dcc_unit[] = {
 };
 
 REG dca_reg[] = {
-  { HRDATA(STATUS, DCAdev.iod_readR[2], 16) },
-  { HRDATA(CWA, DCAdev.iod_CWA, 16) },
-  { HRDATA(NEXT, DCAdev.iod_nextAddr, 16) },
-  { HRDATA(LWA, DCAdev.iod_LWA, 16) },
-  { HRDATA(IENABLE, DCAdev.IENABLE, 16) },
+  { HRDATAD(STATUS, DCAdev.iod_readR[2], 16, "1706 Status") },
+  { HRDATAD(CWA, DCAdev.iod_CWA, 16, "1706 Current Address") },
+  { HRDATAD(NEXT, DCAdev.iod_nextAddr, 16, "Next transfer address") },
+  { HRDATAD(LWA, DCAdev.iod_LWA, 16, "Last word address") },
+  { HRDATAD(IENABLE, DCAdev.IENABLE, 16, "Interrupt enabled") },
   { NULL }
 };
 
 REG dcb_reg[] = {
-  { HRDATA(STATUS, DCBdev.iod_readR[2], 16) },
-  { HRDATA(CWA, DCBdev.iod_CWA, 16) },
-  { HRDATA(NEXT, DCBdev.iod_nextAddr, 16) },
-  { HRDATA(LWA, DCBdev.iod_LWA, 16) },
-  { HRDATA(IENABLE, DCBdev.IENABLE, 16) },
+  { HRDATAD(STATUS, DCBdev.iod_readR[2], 16, "1706 Status") },
+  { HRDATAD(CWA, DCBdev.iod_CWA, 16, "1706 Current Address") },
+  { HRDATAD(NEXT, DCBdev.iod_nextAddr, 16, "Next transfer address") },
+  { HRDATAD(LWA, DCBdev.iod_LWA, 16, "Last word address") },
+  { HRDATAD(IENABLE, DCBdev.IENABLE, 16, "Interrupt enabled") },
   { NULL }
 };
 
 REG dcc_reg[] = {
-  { HRDATA(STATUS, DCCdev.iod_readR[2], 16) },
-  { HRDATA(CWA, DCCdev.iod_CWA, 16) },
-  { HRDATA(NEXT, DCCdev.iod_nextAddr, 16) },
-  { HRDATA(LWA, DCCdev.iod_LWA, 16) },
-  { HRDATA(IENABLE, DCCdev.IENABLE, 16) },
+  { HRDATAD(STATUS, DCCdev.iod_readR[2], 16, "1706 Status") },
+  { HRDATAD(CWA, DCCdev.iod_CWA, 16, "1706 Current Address") },
+  { HRDATAD(NEXT, DCCdev.iod_nextAddr, 16, "Next transfer address") },
+  { HRDATAD(LWA, DCCdev.iod_LWA, 16, "Last word address") },
+  { HRDATAD(IENABLE, DCCdev.IENABLE, 16, "Interrupt enabled") },
   { NULL }
 };
 
 MTAB dc_mod[] = {
-  { MTAB_XTD|MTAB_VDV, 0, "1706-A", NULL, NULL, NULL },
-  { MTAB_XTD|MTAB_VUN, 0, "TARGET", NULL, NULL, &show_target, NULL },
-  { MTAB_XTD|MTAB_VDV|MTAB_VALR, 0, NULL, "INTERRUPT", &set_intr, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "INTERRUPT", NULL, NULL, &show_intr, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "DEBUG", NULL, NULL, &show_debug, NULL },
+  { MTAB_XTD|MTAB_VDV, 0, "1706-A Buffered Data Channel" },
+  { MTAB_XTD|MTAB_VDV, 0, "TARGET", NULL,
+    NULL, &show_target, NULL, "Display devices attached to the data channel" },
+  { MTAB_XTD|MTAB_VDV, 0, "INTERRUPT", "INTERRUPT=hexValue",
+    &set_intr, &show_intr, NULL, "Display data channel interrupt" },
   { 0 }
 };
 
 DEBTAB dc_deb[] = {
-  { "TRACE", DBG_DTRACE },
-  { "STATE", DBG_DSTATE },
-  { "INTR", DBG_DINTR },
-  { "LOCATION", DBG_DLOC },
+  { "TRACE",       DBG_DTRACE,     "Trace device I/O requests" },
+  { "STATE",       DBG_DSTATE,     "Display device state changes" },
+  { "INTR",        DBG_DINTR,      "Display device interrupt requests" },
+  { "LOCATION",    DBG_DLOC,       "Display address for I/O instructions" },
   { "ALL", DBG_DTRACE | DBG_DSTATE | DBG_DINTR | DBG_DLOC },
   { NULL }
 };
@@ -254,12 +254,7 @@ DEVICE dca_dev = {
   NULL, NULL, NULL,
   &DCAdev,
   DEV_DEBUG | DEV_NOEQUIP | DEV_INDEV | DEV_OUTDEV, 0, dc_deb,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL
+  NULL, NULL, &dc_help, NULL, NULL, NULL
 };
 
 DEVICE dcb_dev = {
@@ -269,12 +264,7 @@ DEVICE dcb_dev = {
   NULL, NULL, NULL,
   &DCBdev,
   DEV_DEBUG | DEV_NOEQUIP | DEV_INDEV | DEV_OUTDEV, 0, dc_deb,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL
+  NULL, NULL, &dc_help, NULL, NULL, NULL
 };
 
 DEVICE dcc_dev = {
@@ -284,12 +274,7 @@ DEVICE dcc_dev = {
   NULL, NULL, NULL,
   &DCCdev,
   DEV_DEBUG | DEV_NOEQUIP | DEV_INDEV | DEV_OUTDEV, 0, dc_deb,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL
+  NULL, NULL, &dc_help, NULL, NULL, NULL
 };
 
 static DEVICE *dc_devices[IO_1706_MAX] = {
@@ -541,17 +526,17 @@ t_stat show_intr(FILE *st, UNIT *uptr, int32 val, CONST void *desc)
  */
 t_stat show_target(FILE *st, UNIT *uptr, int32 val, CONST void *desc)
 {
-  DEVICE *dptr;
   IO_DEVICE *iod;
 
   if (uptr == NULL)
     return SCPE_IERR;
 
-  iod = (IO_DEVICE *)uptr->up8;
-  dptr = iod->iod_indev;
+  if ((iod = (IO_DEVICE *)uptr->up8) != NULL) {
+    DEVICE *dptr = iod->iod_indev;
 
-  fprintf(st, "Target: %s (%s), Equip: %d",
-          sim_dname(dptr), iod->iod_model, iod->iod_equip);
+    fprintf(st, "\n\tTarget: %s (%s), Equip: %d",
+            sim_dname(dptr), iod->iod_model, iod->iod_equip);
+  }
   return SCPE_OK;
 }
 
@@ -793,3 +778,30 @@ uint16 dcINTR(void)
 
   return result;
 }
+
+t_stat dc_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
+{
+  const char helpString[] =
+    " The %D device is a 1706-A buffered data channel.\n"
+    "1 Hardware Description\n"
+    " The 1706-A consists of a controller which can control up to 8 other\n"
+    " controllers to provide them with direct memory access. Up to 3\n"
+    " 1706-A's may be connected to the CPU. All 3 buffered data channels are\n"
+    " available in the simulator but only channel 1 (DCA) is connected to a\n"
+    " peripheral (the magtape controller) and only if that controller is\n"
+    " configured as a 1732-A. Unlike actual hardware, the simulator allows\n"
+    " access to the magtape controller either through the A/Q channel or\n"
+    " through a 1706-A.\n\n"
+    " By default, the simulator does not assign an interrupt to a 1706-A. An\n"
+    " interrupt may be assigned with the command:\n\n"
+    "+sim> SET %D INTERRUPT=hexValue\n"
+    "2 Equipment Address\n"
+    " Unlike most peripherals, buffered data channels use private addresses\n"
+    " outside the normal 1 - 15 address range.\n"
+    "2 $Registers\n"
+    "1 Configuration\n"
+    " A %D device is configured with various simh SET commands\n"
+    "2 $Set commands\n";
+
+  return scp_help(st, dptr, uptr, flag, helpString, cptr);
+}
diff --git a/CDC1700/cdc1700_dev1.c b/CDC1700/cdc1700_dev1.c
index e4d03fb7..6e1870e0 100644
--- a/CDC1700/cdc1700_dev1.c
+++ b/CDC1700/cdc1700_dev1.c
@@ -46,7 +46,6 @@ extern void RaiseExternalInterrupt(DEVICE *);
 
 extern t_bool doDirectorFunc(DEVICE *, t_bool);
 
-extern t_stat show_debug(FILE *, UNIT *, int32, CONST void *);
 extern t_stat show_addr(FILE *, UNIT *, int32, CONST void *);
 
 extern t_stat set_stoponrej(UNIT *, int32, CONST char *, void *);
@@ -72,6 +71,8 @@ t_bool TTreject(IO_DEVICE *, t_bool, uint8);
 enum IOstatus TTin(IO_DEVICE *, uint8);
 enum IOstatus TTout(IO_DEVICE *, uint8);
 
+t_stat tt_help(FILE *, DEVICE *, UNIT *, int32, const char *);
+
 /*
         1711-A/B, 1712-A Teletypewriter
 
@@ -189,29 +190,31 @@ uint8 tti_manualIntr = 0x7;
 UNIT tti_unit = { UDATA(&tti_svc, UNIT_IDLE+TT_MODE_KSR+TTUF_HDX, 0), KBD_POLL_WAIT };
 
 REG tti_reg[] = {
-  { HRDATA(MODE, TTdev.iod_rmode, 8) },
-  { HRDATA(FUNCTION, TTdev.FUNCTION, 16) },
-  { HRDATA(STATUS, TTdev.STATUS, 16) },
-  { HRDATA(IENABLE, TTIdev.IENABLE, 16) },
-  { HRDATA(INTRKEY, tti_manualIntr, 8) },
+  { HRDATAD(MODE, TTdev.iod_rmode, 1, "Read/Write mode (Read == TRUE)") },
+  { HRDATAD(FUNCTION, TTdev.FUNCTION, 16, "Last director function issued") },
+  { HRDATAD(STATUS, TTdev.STATUS, 16, "Director status register") },
+  { HRDATAD(IENABLE, TTIdev.IENABLE, 16, "Interrupts enabled") },
+  { HRDATAD(INTRKEY, tti_manualIntr, 8, "Manual interrupt keycode") },
   { NULL }
 };
 
 MTAB tti_mod[] = {
-  { TTUF_HDX, 0, "full duplex", "FDX", NULL },
-  { TTUF_HDX, TTUF_HDX, "half duplex", "HDX", NULL },
-  { MTAB_XTD | MTAB_VDV, 0, "1711-A", NULL, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", NULL, NULL, &show_addr, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "DEBUG", NULL, NULL, &show_debug, NULL },
+  { MTAB_XTD | MTAB_VDV, 0, "1711-A Console Terminal (Input)" },
+  { TTUF_HDX, 0, "full duplex", "FDX",
+    NULL, NULL, NULL, "Set TT device to full duplex" },
+  { TTUF_HDX, TTUF_HDX, "half duplex", "HDX",
+    NULL, NULL, NULL, "Set TT device to half duplex" },
+  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", NULL,
+    NULL, &show_addr, NULL, "Display equipment address" },
   { 0 }
 };
 
 DEBTAB tti_deb[] = {
-  { "TRACE", DBG_DTRACE },
-  { "STATE", DBG_DSTATE },
-  { "INTR", DBG_DINTR },
-  { "LOCATION", DBG_DLOC },
-  { "FIRSTREJ", DBG_DFIRSTREJ },
+  { "TRACE",       DBG_DTRACE,     "Trace device I/O requests" },
+  { "STATE",       DBG_DSTATE,     "Display device state changes" },
+  { "INTR",        DBG_DINTR,      "Display device interrupt requests" },
+  { "LOCATION",    DBG_DLOC,       "Display address of I/O instructions" },
+  { "FIRSTREJ",    DBG_DFIRSTREJ,  "Suppress display of 2nd ... I/O rejects" },
   { "ALL", DBG_DTRACE | DBG_DSTATE | DBG_DLOC },
   { NULL }
 };
@@ -223,8 +226,7 @@ DEVICE tti_dev = {
   NULL, NULL, NULL,
   &TTdev,
   DEV_DEBUG | DEV_NOEQUIP | DEV_INDEV, 0, tti_deb,
-  NULL,
-  NULL
+  NULL, NULL, &tt_help, NULL, NULL, NULL
 };
 
 /* TTO data structures
@@ -238,29 +240,31 @@ DEVICE tti_dev = {
 UNIT tto_unit = { UDATA(&tto_svc, TT_MODE_KSR+TTUF_HDX, 0), TT_OUT_WAIT };
 
 REG tto_reg[] = {
-  { HRDATA(MODE, TTdev.iod_rmode, 8) },
-  { HRDATA(FUNCTION, TTdev.FUNCTION, 16) },
-  { HRDATA(STATUS, TTdev.STATUS, 16) },
-  { HRDATA(IENABLE, TTOdev.IENABLE, 16) },
+  { HRDATAD(MODE, TTdev.iod_rmode, 1, "Read/Write mode (Read == TRUE)") },
+  { HRDATAD(FUNCTION, TTdev.FUNCTION, 16, "Last director function issued") },
+  { HRDATAD(STATUS, TTdev.STATUS, 16, "Director status register") },
+  { HRDATAD(IENABLE, TTOdev.IENABLE, 16, "Interrupts enabled") },
   { NULL }
 };
 
 MTAB tto_mod[] = {
-  { TTUF_HDX, 0, "full duplex", "FDX", NULL },
-  { TTUF_HDX, TTUF_HDX, "half duplex", "HDX", NULL },
-  { MTAB_XTD | MTAB_VDV, 0, "1711-A", NULL, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", NULL, NULL, &show_addr, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "DEBUG", NULL, NULL, &show_debug, NULL },
+  { MTAB_XTD | MTAB_VDV, 0, "1711-A Console Terminal (Output)" },
+  { TTUF_HDX, 0, "full duplex", "FDX",
+    NULL, NULL, NULL, "Set TT device to full duplex" },
+  { TTUF_HDX, TTUF_HDX, "half duplex", "HDX",
+    NULL, NULL, NULL, "Set TT device to half duplex" },
+  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", NULL,
+    NULL, &show_addr, NULL, "Display equipment address" },
   { 0 }
 };
 
 
 DEBTAB tto_deb[] = {
-  { "TRACE", DBG_DTRACE },
-  { "STATE", DBG_DSTATE },
-  { "INTR", DBG_DINTR },
-  { "LOCATION", DBG_DLOC },
-  { "FIRSTREJ", DBG_DFIRSTREJ },
+  { "TRACE",       DBG_DTRACE,     "Trace device I/O requests" },
+  { "STATE",       DBG_DSTATE,     "Display devide state changes" },
+  { "INTR",        DBG_DINTR,      "Display device interrupt requests" },
+  { "LOCATION",    DBG_DLOC,       "Display address for I/O instructions" },
+  { "FIRSTREJ",    DBG_DFIRSTREJ,  "Suppress display of 2nd ... I/O rejects" },
   { "ALL", DBG_DTRACE | DBG_DSTATE | DBG_DLOC },
   { NULL }
 };
@@ -272,8 +276,7 @@ DEVICE tto_dev = {
   NULL, NULL, NULL,
   &TTdev,
   DEV_DEBUG | DEV_NOEQUIP | DEV_OUTDEV, 0, tto_deb,
-  NULL,
-  NULL
+  NULL, NULL, &tt_help, NULL, NULL, NULL
 };
 
 /*
@@ -751,6 +754,34 @@ enum IOstatus TTout(IO_DEVICE *iod, uint8 reg)
   return IO_REPLY;
 }
 
+t_stat tt_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
+{
+  const char helpString[] =
+    /****************************************************************************/
+    " The TTI/TTO device is a 1711-A teletype console. The device is\n"
+    " implemented as 2 seperate devices within the simulator; TTI for input\n"
+    " and TTO for output.\n"
+    "1 Hardware Description\n"
+    " The 1711-A consists of a teletype console terminal with an extra button\n"
+    " which is used to generate a 'manual interrupt'. By default, the\n"
+    " simulator uses the 'Control+G' combination to generate the interrupt.\n"
+    " This key combination may be changed by:\n\n"
+    "+sim> DEPOSIT TTI INTRKEY keycodeValue\n\n"
+    "2 Equipment Address\n"
+    " The console device is part of the low-speed package and, as such, is at\n"
+    " fixed equipment address 1, station 1.\n"
+    "2 $Registers\n"
+    "\n"
+    " These registers contain the emulated state of the device. These values\n"
+    " don't necessarily relate to any detail of the original device being\n"
+    " emulated but are merely internal details of the emulation.\n"
+    "1 Configuration\n"
+    " A %D device is configured with various simh SET commands\n"
+    "2 $Set commands\n";
+
+  return scp_help(st, dptr, uptr, flag, helpString, cptr);
+}
+
 t_stat ptr_svc(UNIT *);
 t_stat ptr_reset(DEVICE *);
 t_stat ptr_attach(UNIT *, CONST char *);
@@ -759,6 +790,8 @@ t_stat ptr_detach(UNIT *);
 enum IOstatus PTRin(IO_DEVICE *, uint8);
 enum IOstatus PTRout(IO_DEVICE *, uint8);
 
+t_stat ptr_help(FILE *, DEVICE *, UNIT *, int32, const char *);
+
 /*
         1721-A/B/C/D, 1722-A/B Paper Tape Reader
 
@@ -837,28 +870,32 @@ UNIT ptr_unit = {
 };
 
 REG ptr_reg[] = {
-  { HRDATA(FUNCTION, PTRdev.FUNCTION, 16) },
-  { HRDATA(STATUS, PTRdev.STATUS, 16) },
-  { HRDATA(IENABLE, PTRdev.IENABLE, 16)},
+  { HRDATAD(FUNCTION, PTRdev.FUNCTION, 16, "Last director function issued") },
+  { HRDATAD(STATUS, PTRdev.STATUS, 16, "Director status register") },
+  { HRDATAD(IENABLE, PTRdev.IENABLE, 16, "Interrupts enabled") },
   { NULL }
 };
 
 MTAB ptr_mod[] = {
-  { MTAB_XTD | MTAB_VDV, 0, "1721-A", NULL, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", "EQUIPMENT", NULL, &show_addr, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "DEBUG", NULL, NULL, &show_debug, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "STOPONREJECT", &set_stoponrej, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOSTOPONREJECT", &clr_stoponrej, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "PROTECT", &set_protected, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT", &clear_protected, NULL, NULL },
+  { MTAB_XTD | MTAB_VDV, 0, "1721-A Paper Tape Reader" },
+  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", NULL,
+    NULL, &show_addr, NULL, "Display equipment address" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "STOPONREJECT",
+    &set_stoponrej, NULL, NULL, "Stop simulation if I/O is rejected" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOSTOPONREJECT",
+    &clr_stoponrej, NULL, NULL, "Don't stop simulation if I/O is rejected" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "PROTECT",
+    &set_protected, NULL, NULL, "Device is protected (unimplemented)" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT",
+    &clear_protected, NULL, NULL, "Device is unprotected (unimplemented)" },
   { 0 }
 };
 
 DEBTAB ptr_deb[] = {
-  { "TRACE", DBG_DTRACE },
-  { "STATE", DBG_DSTATE },
-  { "LOCATION", DBG_DLOC },
-  { "FIRSTREJ", DBG_DFIRSTREJ },
+  { "TRACE",       DBG_DTRACE,     "Traced device I/O requests" },
+  { "STATE",       DBG_DSTATE,     "Display device state changes" },
+  { "LOCATION",    DBG_DLOC,       "Display address of I/O instructions" },
+  { "FIRSTREJ",    DBG_DFIRSTREJ,  "Suppress display of 2nd ... I/O rejected" },
   { "ALL", DBG_DTRACE | DBG_DSTATE | DBG_DLOC },
   { NULL }
 };
@@ -869,7 +906,8 @@ DEVICE ptr_dev = {
   NULL, NULL, &ptr_reset,
   NULL, &ptr_attach, &ptr_detach,
   &PTRdev,
-  DEV_DEBUG | DEV_NOEQUIP | DEV_INDEV | DEV_PROTECT, 0, ptr_deb
+  DEV_DEBUG | DEV_NOEQUIP | DEV_INDEV | DEV_PROTECT, 0, ptr_deb,
+  NULL, NULL, &ptr_help, NULL, NULL, NULL
 };
 
 /*
@@ -1028,12 +1066,38 @@ enum IOstatus PTRout(IO_DEVICE *iod, uint8 reg)
   return IO_REPLY;
 }
 
+t_stat ptr_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
+{
+  const char helpString[] =
+    /****************************************************************************/
+    " The %D device is a 1721-A paper tape reader.\n"
+    "1 Hardware Description\n"
+    " The 1721-A consists of a controller and a physical paper tape reader.\n"
+    "2 Equipment Address\n"
+    " The paper tape reader is part of the low-speed package and, as such, is\n"
+    " at fixed equipment address 1, station 2.\n"
+    "2 $Registers\n"
+    "\n"
+    " These registers contain the emulated state of the device. These values\n"
+    " don't necessarily relate to any detail of the original device being\n"
+    " emulated but are merely internal details of the emulation. STATUS always\n"
+    " contains the current status of the device as it would be read by an\n"
+    " application program.\n"
+    "1 Configuration\n"
+    " A %D device is configured with various simh SET and ATTACH commands\n"
+    "2 $Set commands\n";
+
+  return scp_help(st, dptr, uptr, flag, helpString, cptr);
+}
+
 t_stat ptp_svc(UNIT *);
 t_stat ptp_reset(DEVICE *);
 
 enum IOstatus PTPin(IO_DEVICE *, uint8);
 enum IOstatus PTPout(IO_DEVICE *, uint8);
 
+t_stat ptp_help(FILE *, DEVICE *, UNIT *, int32, const char *);
+
 /*
         1723-A/B, 1724-A/B Paper Tape Punch
 
@@ -1113,28 +1177,32 @@ UNIT ptp_unit = {
 };
 
 REG ptp_reg[] = {
-  { HRDATA(FUNCTION, PTPdev.FUNCTION, 16) },
-  { HRDATA(STATUS, PTPdev.STATUS, 16) },
-  { HRDATA(IENABLE, PTPdev.IENABLE, 16)},
+  { HRDATAD(FUNCTION, PTPdev.FUNCTION, 16, "Last director function issued") },
+  { HRDATAD(STATUS, PTPdev.STATUS, 16, "Director status register") },
+  { HRDATAD(IENABLE, PTPdev.IENABLE, 16, "Interrupts enabled") },
   { NULL }
 };
 
 MTAB ptp_mod[] = {
-  { MTAB_XTD | MTAB_VDV, 0, "1723-A", NULL, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", "EQUIPMENT", NULL, &show_addr, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "DEBUG", NULL, NULL, &show_debug, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "STOPONREJECT",  &set_stoponrej, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOSTOPONREJECT", &clr_stoponrej, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "PROTECT", &set_protected, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT", &clear_protected, NULL, NULL },
+  { MTAB_XTD | MTAB_VDV, 0, "1723-A Paper Tape Punch" },
+  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", NULL,
+    NULL, &show_addr, NULL, "Display equipment address" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "STOPONREJECT",
+    &set_stoponrej, NULL, NULL, "Stop simulation if I/O is rejected" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOSTOPONREJECT",
+    &clr_stoponrej, NULL, NULL, "Don't stop simulation if I/O is rejected" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "PROTECT",
+    &set_protected, NULL, NULL, "Device is protected (unimplemented)" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT",
+    &clear_protected, NULL, NULL, "Device is unprotected (unimplemented)" },
   { 0 }
 };
 
 DEBTAB ptp_deb[] = {
-  { "TRACE", DBG_DTRACE },
-  { "STATE", DBG_DSTATE },
-  { "LOCATION", DBG_DLOC },
-  { "FIRSTREJ", DBG_DFIRSTREJ },
+  { "TRACE",       DBG_DTRACE,     "Trace device I/O requests" },
+  { "STATE",       DBG_DSTATE,     "Display device state changes" },
+  { "LOCATION",    DBG_DLOC,       "Display address of I/O instructions" },
+  { "FIRSTREJ",    DBG_DFIRSTREJ,  "Suppress display of 2nd ... I/O rejects" },
   { "ALL", DBG_DTRACE | DBG_DSTATE | DBG_DLOC },
   { NULL }
 };
@@ -1146,10 +1214,9 @@ DEVICE ptp_dev = {
   NULL, NULL, NULL,
   &PTPdev,
   DEV_DEBUG | DEV_NOEQUIP | DEV_OUTDEV | DEV_PROTECT, 0, ptp_deb,
-  NULL,
-  NULL
+  NULL, NULL, &ptp_help, NULL, NULL, NULL
 };
-
+ 
 /*
  * Dump the current internal state of the PTP device.
  */
@@ -1306,6 +1373,30 @@ enum IOstatus PTPout(IO_DEVICE *iod, uint8 reg)
   return IO_REPLY;
 }
 
+t_stat ptp_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
+{
+  const char helpString[] =
+    /****************************************************************************/
+    " The %D device is a 1723-A paper tape punch.\n"
+    "1 Hardware Description\n"
+    " The 1723-A consists of a controller and a physical paper tape punch.\n"
+    "2 Equipment Address\n"
+    " The paper tape reader is part of the low-speed package and, as such, is\n"
+    " at fixed equipment address 1, station 4.\n"
+    "2 $Registers\n"
+    "\n"
+    " These registers contain the emulated state of the device. These values\n"
+    " don't necessarily relate to any detail of the original device being\n"
+    " emulated but are merely internal details of the emulation. STATUS always\n"
+    " contains the current status of the device as it would be read by an\n"
+    " application program.\n"
+    "1 Configuration\n"
+    " A %D device is configured with various simh SET and ATTACH commands\n"
+    "2 $Set commands\n";
+
+  return scp_help(st, dptr, uptr, flag, helpString, cptr);
+}
+
 t_stat cdr_svc(UNIT *);
 t_stat cdr_reset(DEVICE *);
 
@@ -1382,26 +1473,28 @@ UNIT cdr_unit = {
 };
 
 REG cdr_reg[] = {
-  { HRDATA(FUNCTION, CDRdev.FUNCTION, 16) },
-  { HRDATA(STATUS, CDRdev.STATUS, 16) },
-  { HRDATA(IENABLE, CDRdev.IENABLE, 16)},
+  { HRDATAD(FUNCTION, CDRdev.FUNCTION, 16, "Last director function issued") },
+  { HRDATAD(STATUS, CDRdev.STATUS, 16, "Director status register") },
+  { HRDATAD(IENABLE, CDRdev.IENABLE, 16, "Interrupts enabled") },
   { NULL }
 };
 
 MTAB cdr_mod[] = {
-  { MTAB_XTD | MTAB_VDV, 0, "1729", NULL, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", "EQUIPMENT", NULL, &show_addr, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "DEBUG", NULL, NULL, &show_debug, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "PROTECT", &set_protected, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT", &clear_protected, NULL, NULL },
+  { MTAB_XTD | MTAB_VDV, 0, "1729 Card Reader" },
+  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", NULL,
+    NULL, &show_addr, NULL, "Display equipment address" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "PROTECT",
+    &set_protected, NULL, NULL, "Device is protected (unimplemented)" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT",
+    &clear_protected, NULL, NULL, "Device is unprotected (unimplemented)" },
   { 0 }
 };
 
 DEBTAB cdr_deb[] = {
-  { "TRACE", DBG_DTRACE },
-  { "STATE", DBG_DSTATE },
-  { "LOCATION", DBG_DLOC },
-  { "FIRSTREJ", DBG_DFIRSTREJ },
+  { "TRACE",       DBG_DTRACE,     "Trace device I/O requests" },
+  { "STATE",       DBG_DSTATE,     "Display device state changes" },
+  { "LOCATION",    DBG_DLOC,       "Display address for I/O instructions" },
+  { "FIRSTREJ",    DBG_DFIRSTREJ,  "Suppress display of 2nd ... I/O rejects" },
   { "ALL", DBG_DTRACE | DBG_DSTATE | DBG_DLOC },
   { NULL }
 };
@@ -1413,8 +1506,7 @@ DEVICE cdr_dev = {
   NULL, NULL, NULL,
   &CDRdev,
   DEV_DEBUG | DEV_NOEQUIP | DEV_INDEV | DEV_PROTECT, 0, cdr_deb,
-  NULL,
-  NULL
+  NULL, NULL, NULL, NULL, NULL, NULL
 };
 
 /* Unit service */
diff --git a/CDC1700/cdc1700_dp.c b/CDC1700/cdc1700_dp.c
index 0c2b147a..52a4501e 100644
--- a/CDC1700/cdc1700_dp.c
+++ b/CDC1700/cdc1700_dp.c
@@ -45,7 +45,6 @@ extern void fw_IOintr(t_bool, DEVICE *, IO_DEVICE *, uint16, uint16, uint16, con
 
 extern t_stat checkReset(DEVICE *, uint8);
 
-extern t_stat show_debug(FILE *, UNIT *, int32, CONST void *);
 extern t_stat show_addr(FILE *, UNIT *, int32, CONST void *);
 
 extern t_stat set_protected(UNIT *, int32, CONST char *, void *);
@@ -134,8 +133,10 @@ enum IOstatus DPin(IO_DEVICE *, uint8);
 enum IOstatus DPout(IO_DEVICE *, uint8);
 t_bool DPintr(IO_DEVICE *);
 
+t_stat dp_help(FILE *, DEVICE *, UNIT *, int32, const char *);
+
 /*
-        1738-A/B Disk Pack Controller
+        1738-B Disk Pack Controller
 
    Addresses
                                 Computer Instruction
@@ -257,38 +258,47 @@ UNIT dp_unit[] = {
 };
 
 REG dp_reg[] = {
-  { HRDATA(FUNCTION, DPdev.FUNCTION, 16) },
-  { HRDATA(STATUS, DPdev.STATUS, 16) },
-  { HRDATA(IENABLE, DPdev.IENABLE, 16) },
-  { HRDATA(ADDRSTATUS, DPdev.ADDRSTATUS, 16) },
+  { HRDATAD(FUNCTION, DPdev.FUNCTION, 16, "Last director function issued") },
+  { HRDATAD(STATUS, DPdev.STATUS, 16, "Director status register") },
+  { HRDATAD(IENABLE, DPdev.IENABLE, 16, "Interrupts enabled") },
+  { HRDATAD(ADDRSTATUS, DPdev.ADDRSTATUS, 16, "Address register status") },
   { NULL }
 };
 
 MTAB dp_mod[] = {
-  { MTAB_XTD|MTAB_VDV, 0, "1738-B", NULL, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", NULL, NULL, &show_addr, NULL },
-  { MTAB_XTD|MTAB_VDV|MTAB_VALR, 0, NULL, "EQUIPMENT", &set_equipment, NULL, NULL },
-  { MTAB_XTD|MTAB_VUN, 0, "DRIVE", NULL, NULL, &show_drive, NULL },
-  { MTAB_XTD|MTAB_VUN, 0, NULL, "853", &set_dp853, NULL, NULL },
-  { MTAB_XTD|MTAB_VUN, 0, NULL, "854", &set_dp854, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "DEBUG", NULL, NULL, &show_debug, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "STOPONREJECT", &set_stoponrej, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOSTOPONREJECT", &clr_stoponrej, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL,"PROTECT", &set_protected, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT", &clear_protected, NULL, NULL},
-  { MTAB_XTD|MTAB_VDV, 0, "ADDRESSING", NULL, NULL, &show_addressing, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NORMAL", &set_normal, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "REVERSE", &set_reverse, NULL, NULL },
+  { MTAB_XTD|MTAB_VDV, 0, "1738-B Disk Pack Controller" },
+  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", "EQUIPMENT=hexAddress",
+    &set_equipment, &show_addr, NULL, "Display equipment address" },
+  { MTAB_XTD|MTAB_VUN, 0, "DRIVE", NULL,
+    NULL, &show_drive, NULL, "Display type of drive (853 or 854" },
+  { MTAB_XTD|MTAB_VUN, 0, NULL, "853",
+    &set_dp853, NULL, NULL, "Set drive type to 853" },
+  { MTAB_XTD|MTAB_VUN, 0, NULL, "854",
+    &set_dp854, NULL, NULL, "Set drive type to 854" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "STOPONREJECT",
+    &set_stoponrej, NULL, NULL, "Stop simulation if I/O is rejected" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOSTOPONREJECT",
+    &clr_stoponrej, NULL, NULL, "Don't stop simulation if I/O is rejected" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL,"PROTECT",
+    &set_protected, NULL, NULL, "Device is protected (unimplemented)" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT",
+    &clear_protected, NULL, NULL, "Device is unprotected (unimplemented)"},
+  { MTAB_XTD|MTAB_VDV, 0, "ADDRESSING", NULL,
+    NULL, &show_addressing, NULL, "Display disk addressing mode" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NORMAL",
+    &set_normal, NULL, NULL, "Normal addressing mode: drive 0 then 1" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "REVERSE",
+    &set_reverse, NULL, NULL, "Reverse addressing mode: drive 1 then 0" },
   { 0 }
 };
 
 DEBTAB dp_deb[] = {
-  { "TRACE", DBG_DTRACE },
-  { "STATE", DBG_DSTATE },
-  { "INTR", DBG_DINTR },
-  { "ERROR", DBG_DERROR },
-  { "LOCATION", DBG_DLOC },
-  { "FIRSTREJ", DBG_DFIRSTREJ },
+  { "TRACE",       DBG_DTRACE,     "Trace device I/O requests" },
+  { "STATE",       DBG_DSTATE,     "Display device state changes" },
+  { "INTR",        DBG_DINTR,      "Display device interrupt requests" },
+  { "ERROR",       DBG_DERROR,     "Display device errors" },
+  { "LOCATION",    DBG_DLOC,       "Display address of I/O instructions" },
+  { "FIRSTREJ",    DBG_DFIRSTREJ,  "Suppress display of 2nd ... I/O rejects" },
   { "ALL", DBG_DTRACE | DBG_DSTATE | DBG_DINTR | DBG_DERROR | DBG_DLOC },
   { NULL }
 };
@@ -302,8 +312,7 @@ DEVICE dp_dev = {
   DEV_DEBUG | DEV_DISK | DEV_DISABLE | \
   DEV_DIS | DEV_INDEV | DEV_OUTDEV | DEV_PROTECT,
   0, dp_deb,
-  NULL,
-  NULL
+  NULL, NULL, &dp_help, NULL, NULL, NULL
 };
 
 /*
@@ -1100,3 +1109,38 @@ t_stat DPautoload(void)
   }
   return SCPE_UNATT;
 }
+
+t_stat dp_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
+{
+  const char helpString[] =
+    /****************************************************************************/
+    " The %D device is a 1738-B disk pack controller.\n"
+    "1 Hardware Description\n"
+    " The 1738-B consists of a controller with up to 2 attached disk drives.\n"
+    " The controller includes a jumper which controls which drive is\n"
+    " addressed as logical disk 0:\n\n"
+    "+sim> SET %D NORMAL\n"
+    "+sim> SET %D REVERSE\n\n"
+    " Each physical drive may be configured as a 853 or 854:\n\n"
+    "+853 drive: 1536000 words per drive\n"
+    "+854 drive: 3118080 words per drive\n\n"
+    " The configuration may be changed by:\n\n"
+    "+sim> SET %U 853\n"
+    "+sim> SET %U 854\n"
+    "2 Equipment Address\n"
+    " Disk controllers are typically set to equipment address 3. This address\n"
+    " may be changed by:\n\n"
+    "+sim> SET %D EQUIPMENT=hexValue\n\n"
+    "2 $Registers\n"
+    "\n"
+    " These registers contain the emulated state of the device. These values\n"
+    " don't necessarily relate to any detail of the original device being\n"
+    " emulated but are merely internal details of the emulation. STATUS always\n"
+    " contains the current status of the device as it would be read by an\n"
+    " application program.\n"
+    "1 Configuration\n"
+    " A %D device is configured with various simh SET and ATTACH commands\n"
+    "2 $Set commands\n";
+
+  return scp_help(st, dptr, uptr, flag, helpString, cptr);
+}
diff --git a/CDC1700/cdc1700_io.c b/CDC1700/cdc1700_io.c
index b454944b..724e4809 100644
--- a/CDC1700/cdc1700_io.c
+++ b/CDC1700/cdc1700_io.c
@@ -79,44 +79,6 @@ devIO *IOcall[16];
 DEVICE *IOdev[16];
 devINTR *IOintr[16];
 
-/*
- * Display device debug status
- */
-t_stat show_debug(FILE *st, UNIT *uptr, int32 val, CONST void *desc)
-{
-  DEVICE *dptr;
-  t_bool first = TRUE;
-  DEBTAB *tab;
-
-  if (uptr == NULL)
-    return SCPE_IERR;
-
-  dptr = find_dev_from_unit(uptr);
-  if (dptr == NULL)
-    return SCPE_IERR;
-
-  tab = dptr->debflags;
-  if (tab == NULL)
-    return SCPE_IERR;
-
-  fprintf(st, "Debug: ");
-  if (dptr->dctrl != 0) {
-    uint32 dctrl = dptr->dctrl;
-
-    while ((tab->name != NULL) && (dctrl != 0)) {
-      if ((dctrl & tab->mask) != 0) {
-        if (!first)
-          fprintf(st, ",");
-        fprintf(st, "%s", tab->name);
-        dctrl &= ~tab->mask;
-        first = FALSE;
-      }
-      tab++;
-    }
-  } else fprintf(st, "None");
-  return SCPE_OK;
-}
-
 /*
  * Display equipment/station address, buffered data channel and optional
  * additional information:
@@ -137,7 +99,7 @@ t_stat show_addr(FILE *st, UNIT *uptr, int32 val, CONST void *desc)
     return SCPE_IERR;
 
   iod = (IO_DEVICE *)dptr->ctxt;
-  fprintf(st, "equip: 0x");
+  fprintf(st, "\n\tequip: 0x");
   fprint_val(st, (t_value)iod->iod_equip, DEV_RDX, 16, PV_LEFT);
   if (iod->iod_station != 0xFF) {
     fprintf(st, ", station: ");
diff --git a/CDC1700/cdc1700_lp.c b/CDC1700/cdc1700_lp.c
index 207c4a32..cd0c0d41 100644
--- a/CDC1700/cdc1700_lp.c
+++ b/CDC1700/cdc1700_lp.c
@@ -78,7 +78,6 @@ extern t_bool doDirectorFunc(DEVICE *, t_bool);
 
 extern t_stat checkReset(DEVICE *, uint8);
 
-extern t_stat show_debug(FILE *, UNIT *, int32, CONST void *);
 extern t_stat show_addr(FILE *, UNIT *, int32, CONST void *);
 
 extern t_stat set_stoponrej(UNIT *, int32, CONST char *, void *);
@@ -105,6 +104,8 @@ enum IOstatus LPout(IO_DEVICE *, uint8);
 
 uint8 LPbuf[COLUMNS];
 
+t_stat lp_help(FILE *, DEVICE *, UNIT *, int32, const char *);
+
 /*
         1740, 1742-30 Line Printer
 
@@ -218,31 +219,33 @@ UNIT lp_unit = {
 };
 
 REG lp_reg_1740[] = {
-  { HRDATA(FUNCTION, LPdev.FUNCTION, 16) },
-  { HRDATA(FUNCTION2, LPdev.FUNCTION2, 16) },
-  { HRDATA(STATUS, LPdev.STATUS, 16) },
-  { HRDATA(IENABLE, LPdev.IENABLE, 16) },
+  { HRDATAD(FUNCTION, LPdev.FUNCTION, 16, "Last director function issued") },
+  { HRDATAD(FUNCTION2, LPdev.FUNCTION2, 16, "Last VFC function issued") },
+  { HRDATAD(STATUS, LPdev.STATUS, 16, "Director status register") },
+  { HRDATAD(IENABLE, LPdev.IENABLE, 16, "Interrupts enabled") },
   { NULL }
 };
 
 REG lp_reg_1742[] = {
-  { HRDATA(FUNCTION, LPdev.FUNCTION, 16) },
-  { HRDATA(STATUS, LPdev.STATUS, 16) },
-  { HRDATA(IENABLE, LPdev.IENABLE, 16) },
+  { HRDATAD(FUNCTION, LPdev.FUNCTION, 16, "Last director function issued") },
+  { HRDATAD(STATUS, LPdev.STATUS, 16, "Director status register") },
+  { HRDATAD(IENABLE, LPdev.IENABLE, 16, "Interrupts enabled") },
   { NULL }
 };
 
 MTAB lp_mod[] = {
-  { MTAB_XTD|MTAB_VDV|MTAB_VALR, 0, NULL, "TYPE", &lp_set_type, NULL, NULL,
-    "TYPE={1740|1742}" },
-  { MTAB_XTD|MTAB_VDV, 0, "TYPE", NULL, NULL, &lp_show_type, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV|MTAB_VALR, 0, NULL, "EQUIPMENT", &set_equipment, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", NULL, NULL, &show_addr, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "DEBUG", NULL, NULL, &show_debug, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "STOPONREJECT", &set_stoponrej, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOSTOPONREJECT", &clr_stoponrej, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "PROTECT", &set_protected, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT", &clear_protected, NULL, NULL },
+  { MTAB_XTD|MTAB_VDV, 0, "TYPE", "TYPE={1740|1742}",
+    &lp_set_type, &lp_show_type, NULL, "Display printer controller type" },
+  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", "EQUIPMENT=hexAddress",
+    &set_equipment, &show_addr, NULL, "Display equipment address" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "STOPONREJECT",
+    &set_stoponrej, NULL, NULL, "Stop simulation if I/O is rejected" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOSTOPONREJECT",
+    &clr_stoponrej, NULL, NULL, "Don't stop simulation is I/O is rejected" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "PROTECT",
+    &set_protected, NULL, NULL, "Device is protected (unimplemented)" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT",
+    &clear_protected, NULL, NULL, "Device is unprotected (unimplemented)" },
   { 0 }
 };
 
@@ -254,13 +257,13 @@ MTAB lp_mod[] = {
 #define DBG_CC          (1 << DBG_V_CC)
 
 DEBTAB lp_deb[] = {
-  { "TRACE", DBG_DTRACE },
-  { "STATE", DBG_DSTATE },
-  { "INTR", DBG_DINTR },
-  { "LOCATION", DBG_DLOC },
-  { "FIRSTREJ", DBG_DFIRSTREJ },
+  { "TRACE",       DBG_DTRACE,     "Trace device I/O requests" },
+  { "STATE",       DBG_DSTATE,     "Display device state changes" },
+  { "INTR",        DBG_DINTR,      "Display device interrupt requests" },
+  { "LOCATION",    DBG_DLOC,       "Display address of I/O instructions" },
+  { "FIRSTREJ",    DBG_DFIRSTREJ,  "Suppress display of 2nd ... I/O rejects" },
+  { "CC",          DBG_CC,         "Display carriage control requests" },
   { "ALL", DBG_DTRACE | DBG_DSTATE | DBG_DINTR | DBG_DLOC },
-  { "CC", DBG_CC },
   { NULL }
 };
 
@@ -271,19 +274,18 @@ DEVICE lp_dev = {
   NULL, NULL, NULL,
   &LPdev,
   DEV_DEBUG | DEV_DISABLE | DEV_OUTDEV | DEV_PROTECT, 0, lp_deb,
-  NULL,
-  NULL
+  NULL, NULL, &lp_help, NULL, NULL, NULL
 };
 
 t_stat lp_show_type(FILE *st, UNIT *uptr, int32 val, CONST void *desc)
 {
   switch (LPdev.iod_type) {
     case DEVTYPE_1740:
-      fprintf(st, "1740");
+      fprintf(st, "1740 Line Printer Controller");
       break;
 
     case DEVTYPE_1742:
-      fprintf(st, "1742-30");
+      fprintf(st, "1742-30 Line Printer Controller");
       break;
 
     default:
@@ -652,3 +654,31 @@ enum IOstatus LPout(IO_DEVICE *iod, uint8 reg)
   return IO_REPLY;
 }
 
+t_stat lp_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
+{
+  const char helpString[] =
+    /****************************************************************************/
+    " The %D device is either a 1740 or 1742 line printer controller.\n"
+    "1 Hardware Description\n"
+    " The %D device consists of either a 1740 or 1742 controller along with\n"
+    " a physical line printer. The type of controller present may be changed\n"
+    " by:\n\n"
+    "+sim> SET %D TYPE=1740\n"
+    "+sim> SET %D TYPE=1742\n\n"
+    "2 Equipment Address\n"
+    " Line printer controllers are typically set to equipment address 4. This\n"
+    " address may be changed by:\n\n"
+    "+sim> SET %D EQUIPMENT=hexValue\n\n"
+    "2 $Registers\n"
+    "\n"
+    " These registers contain the emulated state of the device. These values\n"
+    " don't necessarily relate to any detail of the original device being\n"
+    " emulated but are merely internal details of the emulation. STATUS always\n"
+    " contains the current status of the device as it would be read by an\n"
+    " application program.\n"
+    "1 Configuration\n"
+    " A %D device is configured with various simh SET and ATTACH commands\n"
+    "2 $Set commands\n";
+
+  return scp_help(st, dptr, uptr, flag, helpString, cptr);
+}
diff --git a/CDC1700/cdc1700_mt.c b/CDC1700/cdc1700_mt.c
index 903347b1..ce466ae8 100644
--- a/CDC1700/cdc1700_mt.c
+++ b/CDC1700/cdc1700_mt.c
@@ -107,7 +107,6 @@ extern void loadBootstrap(uint16 *, int, uint16, uint16);
 
 extern t_stat checkReset(DEVICE *, uint8);
 
-extern t_stat show_debug(FILE *, UNIT *, int32, CONST void *);
 extern t_stat show_addr(FILE *, UNIT *, int32, CONST void *);
 
 extern t_stat set_protected(UNIT *, int32, CONST char *, void *);
@@ -296,6 +295,8 @@ enum IOstatus MTout(IO_DEVICE *, uint8);
 enum IOstatus MTBDCin(IO_DEVICE *, uint16 *, uint8);
 enum IOstatus MTBDCout(IO_DEVICE *, uint16 *, uint8);
 
+t_stat mt_help(FILE *, DEVICE *, UNIT *, int32, const char *);
+
 /*
         1732-3 Magnetic Tape Controller
 
@@ -450,42 +451,49 @@ UNIT mt_unit[] = {
 };
 
 REG mt_reg_1732_A[] = {
-  { HRDATA(FUNCTION, MTdev.FUNCTION, 16) },
-  { HRDATA(STATUS, MTdev.STATUS, 16) },
-  { HRDATA(UNITSEL, MTdev.iod_writeR[2], 16) },
-  { HRDATA(STATUS2, MTdev.STATUS2, 16) },
-  { HRDATA(IENABLE, MTdev.IENABLE, 16) },
+  { HRDATAD(FUNCTION, MTdev.FUNCTION, 16, "Last director status issued") },
+  { HRDATAD(STATUS, MTdev.STATUS, 16, "Director status register") },
+  { HRDATAD(UNITSEL, MTdev.iod_writeR[2], 16, "Last Unit Select issued") },
+  { HRDATAD(STATUS2, MTdev.STATUS2, 16, "Transport status register") },
+  { HRDATAD(IENABLE, MTdev.IENABLE, 16, "Interrupts enabled") },
   { NULL }
 };
 
 REG mt_reg_1732_3[] = {
-  { HRDATA(FUNCTION, MTdev.FUNCTION, 16) },
-  { HRDATA(STATUS, MTdev.STATUS, 16) },
-  { HRDATA(UNITSEL, MTdev.iod_writeR[2], 16) },
-  { HRDATA(STATUS2, MTdev.STATUS2, 16) },
-  { HRDATA(IENABLE, MTdev.IENABLE, 16) },
-  { HRDATA(BUFFEREDIO, MTdev.BUFFEREDIO, 16) },
-  { HRDATA(CURADDRESS, MTdev.CURADDRESS, 16) },
-  { HRDATA(LASTADDRESS, MTdev.iod_LWA, 16) },
+  { HRDATAD(FUNCTION, MTdev.FUNCTION, 16, "Last director status issued") },
+  { HRDATAD(STATUS, MTdev.STATUS, 16, "Director status register") },
+  { HRDATAD(UNITSEL, MTdev.iod_writeR[2], 16, "Last Unit Select issued") },
+  { HRDATAD(STATUS2, MTdev.STATUS2, 16, "Transport status register") },
+  { HRDATAD(IENABLE, MTdev.IENABLE, 16, "Interrupts enabled") },
+  { HRDATAD(BUFFEREDIO, MTdev.BUFFEREDIO, 16, "Last Buffered I/O issued") },
+  { HRDATAD(CURADDRESS, MTdev.CURADDRESS, 16, "Current DSA address") },
+  { HRDATAD(LASTADDRESS, MTdev.iod_LWA, 16, "Last DSA address") },
   { NULL }
 };
 
 MTAB mt_mod[] = {
-  { MTUF_WLK, 0, "write enabled", "WRITEENABLED", &mt_vlock },
-  { MTUF_WLK, MTUF_WLK, "write locked", "LOCKED", &mt_vlock },
-  { MTAB_XTD|MTAB_VUN, 0, "FORMAT", "FORMAT", &sim_tape_set_fmt, &sim_tape_show_fmt, NULL },
-  { MTAB_XTD|MTAB_VUN, 0, "CAPACITY", "CAPACITY", &sim_tape_set_capac, &sim_tape_show_capac, NULL },
-  { MTAB_XTD|MTAB_VDV|MTAB_VALR, 0, NULL, "TYPE", &mt_set_type, NULL, NULL,
-    "TYPE={1732-A|1732-3}" },
-  { MTAB_XTD|MTAB_VDV, 0, "TYPE", NULL, NULL, &mt_show_type, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", NULL, NULL, &show_addr, NULL },
-  { MTAB_XTD|MTAB_VDV|MTAB_VALR, 0, NULL, "EQUIPMENT", &set_equipment, NULL, NULL },
-  { MTAB_XTD|MTAB_VUN, 0, "TRANSPORT", NULL, NULL, &mt_show_transport, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "DEBUG", NULL, NULL, &show_debug, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "STOPONREJECT", &set_stoponrej, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOSTOPONREJECT", &clr_stoponrej, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "PROTECT", &set_protected, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT", &clear_protected, NULL, NULL },
+  { MTAB_XTD|MTAB_VDV, 0, "TYPE", "TYPE={1732-A|1732-3}",
+    &mt_set_type, &mt_show_type, NULL, "Set/Display magtape controller type" },
+  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", "EQUIPMENT=hexAddress",
+    &set_equipment, &show_addr, NULL, "Set/Display equipment address" },
+  { MTUF_WLK, 0, "write enabled", "WRITEENABLED",
+    &mt_vlock, NULL, NULL, "Mark transport as write enabled" },
+  { MTUF_WLK, MTUF_WLK, "write locked", "LOCKED",
+    &mt_vlock, NULL, NULL, "Mark transport as writed locked" },
+  { MTAB_XTD|MTAB_VUN, 0, "FORMAT", "FORMAT",
+    &sim_tape_set_fmt, &sim_tape_show_fmt, NULL, "Define tape format" },
+  { MTAB_XTD|MTAB_VUN, 0, "CAPACITY", "CAPACITY",
+    &sim_tape_set_capac, &sim_tape_show_capac, NULL, "Specify tape capacity" },
+  { MTAB_XTD|MTAB_VUN, 0, "TRANSPORT", NULL,
+    NULL, &mt_show_transport, NULL, "Display type of tape transport" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "STOPONREJECT",
+    &set_stoponrej, NULL, NULL, "Stop simulation if I/O is rejected" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOSTOPONREJECT",
+    &clr_stoponrej, NULL, NULL, "Don't stop simulation if I/O is rejected" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "PROTECT",
+    &set_protected, NULL, NULL, "Device is protected (unimplemented)" },
+  { MTAB_XTD|MTAB_VDV, 0, NULL, "NOPROTECT",
+    &clear_protected, NULL, NULL, "Device is unprotected (unimplemented)" },
   { 0 }
 };
 
@@ -509,18 +517,18 @@ MTAB mt_mod[] = {
 #define DBG_SELECT      (1 << DBG_V_SELECT)
 
 DEBTAB mt_deb[] = {
-  { "STATE", DBG_DSTATE },
-  { "TRACE", DBG_DTRACE },
-  { "INTR", DBG_DINTR },
-  { "LOCATION", DBG_DLOC },
-  { "FIRSTREJ", DBG_DFIRSTREJ },
-  { "OPS", DBG_OPS },
-  { "READ", DBG_READ },
-  { "RDATA", DBG_RDATA },
-  { "WDATA", DBG_WDATA },
-  { "MTIO", DBG_MTIO },
-  { "DENS", DBG_DENS },
-  { "SELECT", DBG_SELECT },
+  { "TRACE",       DBG_DTRACE,     "Trace device I/O requests" },
+  { "STATE",       DBG_DSTATE,     "Display device state changes" },
+  { "INTR",        DBG_DINTR,      "Display device interrupt requests" },
+  { "LOCATION",    DBG_DLOC,       "Display address of I/O instructions" },
+  { "FIRSTREJ",    DBG_DFIRSTREJ,  "Suppress display of 2nd ... I/O rejects" },
+  { "OPS",         DBG_OPS,        "Trace tape transport operations" },
+  { "READ",        DBG_READ,       "Dump read records" },
+  { "RDATA",       DBG_RDATA,      "Dump programmed I/O read data" },
+  { "WDATA",       DBG_WDATA,      "Dump programmed I/O write data" },
+  { "MTIO",        DBG_MTIO,       "Trace tape library routine calls" },
+  { "DENS",        DBG_DENS,       "Trace denisty select changes" },
+  { "SELECT",      DBG_SELECT,     "Trace transport select/de-select" },
   { NULL }
 };
 
@@ -532,8 +540,7 @@ DEVICE mt_dev = {
   &MTdev,
   DEV_DEBUG | DEV_TAPE | DEV_DISABLE | DEV_INDEV | DEV_OUTDEV | DEV_PROTECT,
   0, mt_deb,
-  NULL,
-  NULL
+  NULL, NULL, &mt_help, NULL, NULL, NULL
 };
 
 /* MT trace routine */
@@ -777,11 +784,11 @@ t_stat mt_show_type(FILE *st, UNIT *uptr, int32 val, CONST void *desc)
 {
   switch (MTdev.iod_type) {
     case DEVTYPE_1732_A:
-      fprintf(st, "1732-A");
+      fprintf(st, "1732-A Magnetic Tape Controller");
       break;
 
     case DEVTYPE_1732_3:
-      fprintf(st, "1733-3");
+      fprintf(st, "1733-3 Magnetic Tape Controller");
       break;
 
     default:
@@ -1971,3 +1978,43 @@ enum IOstatus MTBDCout(IO_DEVICE *iod, uint16 *data, uint8 reg)
   }
   return IO_REJECT;
 }
+
+t_stat mt_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
+{
+  const char helpString[] =
+    /****************************************************************************/
+    " The %D device is either a 1732-A or 1732-3 magtape controller.\n"
+    "1 Hardware Description\n"
+    " The %D device consists of either a 1732-A or 1732-3 controller along\n"
+    " with 4 tape transports. The type con controller present may be changed\n"
+    " by:\n\n"
+    "+sim> SET %D 1732-A\n"
+    "+sim> SET %D 1732-3\n\n"
+    " The first 3 transports (MT0, MT1, MT2) are 9-track drives and MT3 is a\n"
+    " 7-track drive. Each drive may be individually write-locked or\n"
+    " write-enabled with:\n\n"
+    "+sim> SET %U LOCKED\n"
+    "+sim> SET %U WRITEENABLED\n\n"
+    " The 1732-A controller can only perform I/O 1 or 2 bytes at a time. In\n"
+    " order to use DMA it must be coupled with a 1706-A. Due to the lack of\n"
+    " DMA it can only support 200, 556 and 800 BPI on 9-track transports.\n\n"
+    " The 1732-3 is a newer controller which has DMA capability built in. It\n"
+    " loses the ability to handle 200 BPI tape but adds the ability to access\n"
+    " 1600 BPI phase encoded tapes.\n"
+    "2 Equipment Address\n"
+    " Magtape controllers are typically set to equipment address 7. This\n"
+    " address may be changed by:\n\n"
+    "+sim> SET %D EQUIPMENT=hexValue\n\n"
+    "2 $Registers\n"
+    "\n"
+    " These registers contain the emulated state of the device. These values\n"
+    " don't necessarily relate to any detail of the original device being\n"
+    " emulated but are merely internal details of the emulation. STATUS and\n"
+    " STATUS2 always contains the current status of the device as it would be\n"
+    " read by an application program.\n"
+    "1 Configuration\n"
+    " A %D device is configured with various simh SET and ATTACH commands\n"
+    "2 $Set commands\n";
+
+  return scp_help(st, dptr, uptr, flag, helpString, cptr);
+}
diff --git a/CDC1700/cdc1700_rtc.c b/CDC1700/cdc1700_rtc.c
index ddc5dc1e..ceeab5c2 100644
--- a/CDC1700/cdc1700_rtc.c
+++ b/CDC1700/cdc1700_rtc.c
@@ -37,7 +37,6 @@ extern char INTprefix[];
 
 extern t_stat checkReset(DEVICE *, uint8);
 
-extern t_stat show_debug(FILE *, UNIT *, int32, CONST void *);
 extern t_stat show_addr(FILE *, UNIT *, int32, CONST void *);
 
 extern t_stat set_equipment(UNIT *, int32, CONST char *, void *);
@@ -60,6 +59,8 @@ enum IOstatus RTCout(IO_DEVICE *, uint8);
 t_stat rtc_svc(UNIT *);
 t_stat rtc_reset(DEVICE *);
 
+t_stat rtc_help(FILE *, DEVICE *, UNIT *, int32, const char *);
+
 /*
         10336-1 Real-Time Clock
 
@@ -161,25 +162,23 @@ UNIT rtc_unit = {
 };
 
 REG rtc_reg[] = {
-  { HRDATA(FUNCTION, RTCdev.FUNCTION, 16) },
-  { HRDATA(COUNTER, RTCdev.COUNTER, 16) },
-  { HRDATA(HOLDING, RTCdev.HOLDREG, 16) },
+  { HRDATAD(FUNCTION, RTCdev.FUNCTION, 16, "Last director function issued") },
+  { HRDATAD(COUNTER, RTCdev.COUNTER, 16, "Counter register") },
+  { HRDATAD(HOLDING, RTCdev.HOLDREG, 16, "Hold register") },
   { NULL }
 };
 
 MTAB rtc_mod[] = {
-  { MTAB_XTD|MTAB_VDV, 0, "10336-1", NULL, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV|MTAB_VALR, 0, NULL, "RATE", &rtc_set_rate, NULL, NULL,
-    "val={1usec|10usec|100usec|1msec|10msec|100msec|1second}" },
-  { MTAB_XTD|MTAB_VDV, 0, "RATE", NULL, NULL, &rtc_show_rate, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", NULL, NULL, &show_addr, NULL },
-  { MTAB_XTD|MTAB_VDV|MTAB_VALR, 0, NULL, "EQUIPMENT", &set_equipment, NULL, NULL },
-  { MTAB_XTD|MTAB_VDV, 0, "DEBUG", NULL, NULL, &show_debug, NULL },
+  { MTAB_XTD|MTAB_VDV, 0, "10336-1 Real Time Clock" },
+  { MTAB_XTD|MTAB_VDV, 0, "EQUIPMENT", "EQUIPMENT=hexAddress",
+    &set_equipment, &show_addr, NULL, "Display equipment address" },
+  { MTAB_XTD|MTAB_VDV, 0, "RATE", "RATE={1usec|10usec|100usec|1msec|10msec|100msec|1second}",
+    &rtc_set_rate, &rtc_show_rate, NULL, "Show timer tick interval" },
   { 0 }
 };
 
 DEBTAB rtc_deb[] = {
-  { "TRACE", DBG_DTRACE },
+  { "TRACE",       DBG_DTRACE,     "Trace device I/O requests" },
   { NULL }
 };
 
@@ -190,8 +189,7 @@ DEVICE rtc_dev = {
   NULL, NULL, NULL,
   &RTCdev,
   DEV_DEBUG | DEV_DISABLE, 0, rtc_deb,
-  NULL,
-  NULL
+  NULL, NULL, &rtc_help, NULL, NULL, NULL
 };
 
 t_stat rtc_show_rate(FILE *st, UNIT *uptr, int32 val, CONST void *desc)
@@ -339,3 +337,35 @@ enum IOstatus RTCout(IO_DEVICE *iod, uint8 reg)
   }
   return IO_REPLY;
 }
+
+t_stat rtc_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
+{
+  const char helpString[] =
+    /****************************************************************************/
+    " The %D device 10336-1 Real Time Clock.\n"
+    "1 Hardware Description\n"
+    " The 10336-1 is a Real Time Clock which can generate periodic interrupts\n"
+    " or measure elapsed time. The timer resolution is set via jumpers on the\n"
+    " physical hardware. For the simulator, the resolution can be changed by:\n\n"
+    "+sim> SET %D RATE=1usec\n"
+    "+sim> SET %D RATE=10usec\n"
+    "+sim> SET %D RATE=100usec\n"
+    "+sim> SET %D RATE=1msec\n"
+    "+sim> SET %D RATE=10msec\n"
+    "+sim> SET %D RATE=100msec\n"
+    "+sim> SET %D RATE=1second\n\n"
+    "2 Equipment Address\n"
+    " The %D device is set to equipment address 13. This address may be\n"
+    " changed by:\n\n"
+    "+sim> SET %D EQUIPMENT=hexValue\n\n"
+    "2 $Registers\n"
+    "\n"
+    " These registers contain the emulated state of the device. These values\n"
+    " don't necessarily relate to any detail of the original device being\n"
+    " emulated but are merely internal details of the emulation.\n"
+    "1 Configuration\n"
+    " A %D device is configured with various simh SET commands\n"
+    "2 $Set commands\n";
+
+  return scp_help(st, dptr, uptr, flag, helpString, cptr);
+}