diff --git a/VAX/vax750_stddev.c b/VAX/vax750_stddev.c
index 9e62811c..78355848 100644
--- a/VAX/vax750_stddev.c
+++ b/VAX/vax750_stddev.c
@@ -182,6 +182,7 @@ int32 tmr_poll = CLK_DELAY;                             /* pgm timer poll */
 struct todr_battery_info {
     uint32 toy_gmtbase;                                 /* GMT base of set value */
     uint32 toy_gmtbasemsec;                             /* The milliseconds of the set value */
+    uint32 toy_endian_plus2;                            /* 2 -> Big Endian, 3 -> Little Endian, invalid otherwise */
     };
 typedef struct todr_battery_info TOY;
 
@@ -534,7 +535,7 @@ t_stat tti_svc (UNIT *uptr)
 {
 int32 c;
 
-sim_clock_coschedule (uptr, tmxr_poll);                 /* continue poll */
+sim_clock_coschedule_tmr (uptr, TMR_CLK, tmxr_poll);    /* continue poll */
 
 if ((tti_csr & CSR_DONE) &&                             /* input still pending and < 500ms? */
     ((sim_os_msec () - tti_buftime) < 500))
@@ -842,6 +843,20 @@ const char *clk_description (DEVICE *dptr)
 return "time of year clock";
 }
 
+static uint32 sim_byteswap32 (uint32 data)
+{
+uint8 *bdata = (uint8 *)&data;
+uint8 tmp;
+
+tmp = bdata[0];
+bdata[0] = bdata[3];
+bdata[3] = tmp;
+tmp = bdata[1];
+bdata[1] = bdata[2];
+bdata[2] = tmp;
+return data;
+}
+
 /* CLK attach */
 
 t_stat clk_attach (UNIT *uptr, CONST char *cptr)
@@ -853,8 +868,21 @@ memset (uptr->filebuf, 0, (size_t)uptr->capac);
 r = attach_unit (uptr, cptr);
 if (r != SCPE_OK)
     uptr->flags = uptr->flags & ~(UNIT_ATTABLE | UNIT_BUFABLE);
-else
+else {
+    TOY *toy = (TOY *)uptr->filebuf;
+
     uptr->hwmark = (uint32) uptr->capac;
+    if ((toy->toy_endian_plus2 < 2) || (toy->toy_endian_plus2 > 3))
+        memset (uptr->filebuf, 0, (size_t)uptr->capac);
+    else {
+        if (toy->toy_endian_plus2 != sim_end + 2) {     /* wrong endian? */
+            toy->toy_gmtbase = sim_byteswap32 (toy->toy_gmtbase);
+            toy->toy_gmtbasemsec = sim_byteswap32 (toy->toy_gmtbasemsec);
+            }
+        }
+    toy->toy_endian_plus2 = sim_end + 2;
+    todr_resync ();
+    }
 return r;
 }
 
@@ -897,10 +925,18 @@ int32 todr_rd (void)
 TOY *toy = (TOY *)clk_unit.filebuf;
 struct timespec base, now, val;
 
+/* Maximum number of seconds which can be represented as 10ms ticks 
+   in the 32bit TODR.  This is the 33bit value 0x100000000/100 to get seconds */
+#define TOY_MAX_SECS (0x40000000/25)
+
 sim_rtcn_get_time(&now, TMR_CLK);                       /* get curr time */
 base.tv_sec = toy->toy_gmtbase;
 base.tv_nsec = toy->toy_gmtbasemsec * 1000000;
 sim_timespec_diff (&val, &now, &base);
+
+if ((val.tv_sec >= TOY_MAX_SECS) || (!toy->toy_gmtbase))/* todr overflowed? */
+    return 0;                                           /* stop counting */
+
 return (int32)(val.tv_sec*100 + val.tv_nsec/10000000);  /* 100hz Clock Ticks */
 }
 
@@ -910,15 +946,21 @@ void todr_wr (int32 data)
 TOY *toy = (TOY *)clk_unit.filebuf;
 struct timespec now, val, base;
 
-/* Save the GMT time when set value was 0 to record the base for future 
-   read operations in "battery backed-up" state */
+if (data) {
+    /* Save the GMT time when set value was not 0 to record the base for 
+       future read operations in "battery backed-up" state */
 
-sim_rtcn_get_time(&now, TMR_CLK);                       /* get curr time */
-val.tv_sec = ((uint32)data) / 100;
-val.tv_nsec = (((uint32)data) % 100) * 10000000;
-sim_timespec_diff (&base, &now, &val);                  /* base = now - data */
-toy->toy_gmtbase = (uint32)base.tv_sec;
-toy->toy_gmtbasemsec = base.tv_nsec/1000000;
+    sim_rtcn_get_time(&now, TMR_CLK);                       /* get curr time */
+    val.tv_sec = ((uint32)data) / 100;
+    val.tv_nsec = (((uint32)data) % 100) * 10000000;
+    sim_timespec_diff (&base, &now, &val);                  /* base = now - data */
+    toy->toy_gmtbase = (uint32)base.tv_sec;
+    toy->toy_gmtbasemsec = base.tv_nsec/1000000;
+    }
+else {                                                      /* stop the clock */
+    toy->toy_gmtbase = 0;
+    toy->toy_gmtbasemsec = 0;
+    }
 }
 
 t_stat todr_resync (void)
diff --git a/VAX/vax780_stddev.c b/VAX/vax780_stddev.c
index a6bf3738..68c3b707 100644
--- a/VAX/vax780_stddev.c
+++ b/VAX/vax780_stddev.c
@@ -213,6 +213,7 @@ int32 tmr_poll = CLK_DELAY;                             /* pgm timer poll */
 struct todr_battery_info {
     uint32 toy_gmtbase;                                 /* GMT base of set value */
     uint32 toy_gmtbasemsec;                             /* The milliseconds of the set value */
+    uint32 toy_endian_plus2;                            /* 2 -> Big Endian, 3 -> Little Endian, invalid otherwise */
     };
 typedef struct todr_battery_info TOY;
 
@@ -502,7 +503,7 @@ t_stat tti_svc (UNIT *uptr)
 {
 int32 c;
 
-sim_clock_coschedule (uptr, tmxr_poll);                 /* continue poll */
+sim_clock_coschedule_tmr (uptr, TMR_CLK, tmxr_poll);    /* continue poll */
 
 if ((tti_csr & CSR_DONE) &&                             /* input still pending and < 500ms? */
     ((sim_os_msec () - tti_buftime) < 500))
@@ -784,6 +785,20 @@ const char *clk_description (DEVICE *dptr)
 return "time of year clock";
 }
 
+static uint32 sim_byteswap32 (uint32 data)
+{
+uint8 *bdata = (uint8 *)&data;
+uint8 tmp;
+
+tmp = bdata[0];
+bdata[0] = bdata[3];
+bdata[3] = tmp;
+tmp = bdata[1];
+bdata[1] = bdata[2];
+bdata[2] = tmp;
+return data;
+}
+
 /* CLK attach */
 
 t_stat clk_attach (UNIT *uptr, CONST char *cptr)
@@ -795,8 +810,21 @@ memset (uptr->filebuf, 0, (size_t)uptr->capac);
 r = attach_unit (uptr, cptr);
 if (r != SCPE_OK)
     uptr->flags = uptr->flags & ~(UNIT_ATTABLE | UNIT_BUFABLE);
-else
+else {
+    TOY *toy = (TOY *)uptr->filebuf;
+
     uptr->hwmark = (uint32) uptr->capac;
+    if ((toy->toy_endian_plus2 < 2) || (toy->toy_endian_plus2 > 3))
+        memset (uptr->filebuf, 0, (size_t)uptr->capac);
+    else {
+        if (toy->toy_endian_plus2 != sim_end + 2) {     /* wrong endian? */
+            toy->toy_gmtbase = sim_byteswap32 (toy->toy_gmtbase);
+            toy->toy_gmtbasemsec = sim_byteswap32 (toy->toy_gmtbasemsec);
+            }
+        }
+    toy->toy_endian_plus2 = sim_end + 2;
+    todr_resync ();
+    }
 return r;
 }
 
@@ -850,8 +878,8 @@ void todr_wr (int32 data)
 TOY *toy = (TOY *)clk_unit.filebuf;
 struct timespec now, val, base;
 
-/* Save the GMT time when set value was 0 to record the base for future 
-   read operations in "battery backed-up" state */
+/* Save the GMT time when set value was written to record the base for 
+   future read operations in "battery backed-up" state */
 
 sim_rtcn_get_time(&now, TMR_CLK);                       /* get curr time */
 val.tv_sec = ((uint32)data) / 100;
@@ -881,9 +909,9 @@ else {                                                  /* Not-Attached means */
     if (ctm == NULL)                                    /* error? */
         return SCPE_NOFNC;
     base = (((((ctm->tm_yday * 24) +                    /* sec since 1-Jan */
-            ctm->tm_hour) * 60) +
-            ctm->tm_min) * 60) +
-            ctm->tm_sec;
+               ctm->tm_hour) * 60) +
+             ctm->tm_min) * 60) +
+           ctm->tm_sec;
     todr_wr ((base * 100) + 0x10000000);                /* use VMS form */
     }
 return SCPE_OK;
diff --git a/VAX/vax860_stddev.c b/VAX/vax860_stddev.c
index 4178f036..b3396932 100644
--- a/VAX/vax860_stddev.c
+++ b/VAX/vax860_stddev.c
@@ -212,6 +212,7 @@ int32 tmr_poll = CLK_DELAY;                             /* pgm timer poll */
 struct todr_battery_info {
     uint32 toy_gmtbase;                                 /* GMT base of set value */
     uint32 toy_gmtbasemsec;                             /* The milliseconds of the set value */
+    uint32 toy_endian_plus2;                            /* 2 -> Big Endian, 3 -> Little Endian, invalid otherwise */
     };
 typedef struct todr_battery_info TOY;
 
@@ -590,7 +591,7 @@ int32 line = uptr - tti_dev.units;
 switch (line) {
 
     case ID_CT:                                         /* console terminal */
-        sim_clock_coschedule (uptr, tmxr_poll);         /* continue poll */
+        sim_clock_coschedule_tmr (uptr, TMR_CLK, tmxr_poll);/* continue poll */
         if ((tti_csr & CSR_DONE) &&                     /* input still pending and < 500ms? */
             ((sim_os_msec () - tti_buftime) < 500))
              return SCPE_OK;
@@ -910,6 +911,20 @@ const char *clk_description (DEVICE *dptr)
 return "time of year clock";
 }
 
+static uint32 sim_byteswap32 (uint32 data)
+{
+uint8 *bdata = (uint8 *)&data;
+uint8 tmp;
+
+tmp = bdata[0];
+bdata[0] = bdata[3];
+bdata[3] = tmp;
+tmp = bdata[1];
+bdata[1] = bdata[2];
+bdata[2] = tmp;
+return data;
+}
+
 /* CLK attach */
 
 t_stat clk_attach (UNIT *uptr, CONST char *cptr)
@@ -921,8 +936,21 @@ memset (uptr->filebuf, 0, (size_t)uptr->capac);
 r = attach_unit (uptr, cptr);
 if (r != SCPE_OK)
     uptr->flags = uptr->flags & ~(UNIT_ATTABLE | UNIT_BUFABLE);
-else
+else {
+    TOY *toy = (TOY *)uptr->filebuf;
+
     uptr->hwmark = (uint32) uptr->capac;
+    if ((toy->toy_endian_plus2 < 2) || (toy->toy_endian_plus2 > 3))
+        memset (uptr->filebuf, 0, (size_t)uptr->capac);
+    else {
+        if (toy->toy_endian_plus2 != sim_end + 2) {     /* wrong endian? */
+            toy->toy_gmtbase = sim_byteswap32 (toy->toy_gmtbase);
+            toy->toy_gmtbasemsec = sim_byteswap32 (toy->toy_gmtbasemsec);
+            }
+        }
+    toy->toy_endian_plus2 = sim_end + 2;
+    todr_resync ();
+    }
 return r;
 }
 
@@ -976,8 +1004,8 @@ void todr_wr (int32 data)
 TOY *toy = (TOY *)clk_unit.filebuf;
 struct timespec now, val, base;
 
-/* Save the GMT time when set value was 0 to record the base for future 
-   read operations in "battery backed-up" state */
+/* Save the GMT time when set value was 0 to record the base for 
+   future read operations in "battery backed-up" state */
 
 sim_rtcn_get_time(&now, TMR_CLK);                       /* get curr time */
 val.tv_sec = ((uint32)data) / 100;
diff --git a/VAX/vax_stddev.c b/VAX/vax_stddev.c
index eb124cc3..abfc8f72 100644
--- a/VAX/vax_stddev.c
+++ b/VAX/vax_stddev.c
@@ -103,6 +103,7 @@ int32 todr_blow = 1;                                    /* TODR battery low */
 struct todr_battery_info {
     uint32 toy_gmtbase;                                 /* GMT base of set value */
     uint32 toy_gmtbasemsec;                             /* The milliseconds of the set value */
+    uint32 toy_endian_plus2;                            /* 2 -> Big Endian, 3 -> Little Endian, invalid otherwise */
     };
 typedef struct todr_battery_info TOY;
 int32 tmxr_poll = CLK_DELAY * TMXR_MULT;                /* term mux poll */
@@ -344,7 +345,7 @@ t_stat tti_svc (UNIT *uptr)
 {
 int32 c;
 
-sim_clock_coschedule (uptr, tmxr_poll);                 /* continue poll */
+sim_clock_coschedule_tmr (uptr, TMR_CLK, tmxr_poll);    /* continue poll */
 
 if ((tti_csr & CSR_DONE) &&                             /* input still pending and < 500ms? */
     ((sim_os_msec () - tti_buftime) < 500))
@@ -464,6 +465,7 @@ tmr_poll = t;                                           /* set tmr poll */
 tmxr_poll = t * TMXR_MULT;                              /* set mux poll */
 if (!todr_blow && todr_reg)                             /* if running? */
     todr_reg = todr_reg + 1;                            /* incr TODR */
+AIO_SET_INTERRUPT_LATENCY(tmr_poll*clk_tps);            /* set interrrupt latency */
 return SCPE_OK;
 }
 
@@ -506,18 +508,23 @@ void todr_wr (int32 data)
 TOY *toy = (TOY *)clk_unit.filebuf;
 struct timespec now, val, base;
 
-/* Save the GMT time when set value was 0 to record the base for future 
-   read operations in "battery backed-up" state */
-
-sim_rtcn_get_time(&now, TMR_CLK);                       /* get curr time */
-val.tv_sec = ((uint32)data) / 100;
-val.tv_nsec = (((uint32)data) % 100) * 10000000;
-sim_timespec_diff (&base, &now, &val);                  /* base = now - data */
-toy->toy_gmtbase = (uint32)base.tv_sec;
-toy->toy_gmtbasemsec = base.tv_nsec/1000000;
-todr_reg = data;
-if (data)
+if (data) {
     todr_blow = 0;
+    /* Save the GMT time when set value is not 0 to record the base for 
+       future read operations in "battery backed-up" state */
+
+    sim_rtcn_get_time(&now, TMR_CLK);                       /* get curr time */
+    val.tv_sec = ((uint32)data) / 100;
+    val.tv_nsec = (((uint32)data) % 100) * 10000000;
+    sim_timespec_diff (&base, &now, &val);                  /* base = now - data */
+    toy->toy_gmtbase = (uint32)base.tv_sec;
+    toy->toy_gmtbasemsec = base.tv_nsec/1000000;
+    }
+else {                                                      /* stop the clock */
+    toy->toy_gmtbase = 0;
+    toy->toy_gmtbasemsec = 0;
+    }
+todr_reg = data;
 sim_debug (DBG_REG, &clk_dev, "todr_wr(0x%X) - TODR=0x%X blow=%d\n", data, todr_reg, todr_blow);
 }
 
@@ -543,9 +550,9 @@ else {                                                  /* Not-Attached means */
     if (ctm == NULL)                                    /* error? */
         return SCPE_NOFNC;
     base = (((((ctm->tm_yday * 24) +                    /* sec since 1-Jan */
-            ctm->tm_hour) * 60) +
-            ctm->tm_min) * 60) +
-            ctm->tm_sec;
+               ctm->tm_hour) * 60) +
+             ctm->tm_min) * 60) +
+           ctm->tm_sec;
     todr_wr ((base * 100) + 0x10000000);                /* use VMS form */
     }
 return SCPE_OK;
@@ -610,6 +617,20 @@ const char *clk_description (DEVICE *dptr)
 return "time of year clock";
 }
 
+static uint32 sim_byteswap32 (uint32 data)
+{
+uint8 *bdata = (uint8 *)&data;
+uint8 tmp;
+
+tmp = bdata[0];
+bdata[0] = bdata[3];
+bdata[3] = tmp;
+tmp = bdata[1];
+bdata[1] = bdata[2];
+bdata[2] = tmp;
+return data;
+}
+
 /* CLK attach */
 
 t_stat clk_attach (UNIT *uptr, CONST char *cptr)
@@ -621,8 +642,21 @@ memset (uptr->filebuf, 0, (size_t)uptr->capac);
 r = attach_unit (uptr, cptr);
 if (r != SCPE_OK)
     uptr->flags = uptr->flags & ~(UNIT_ATTABLE | UNIT_BUFABLE);
-else
+else {
+    TOY *toy = (TOY *)uptr->filebuf;
+
     uptr->hwmark = (uint32) uptr->capac;
+    if ((toy->toy_endian_plus2 < 2) || (toy->toy_endian_plus2 > 3))
+        memset (uptr->filebuf, 0, (size_t)uptr->capac);
+    else {
+        if (toy->toy_endian_plus2 != sim_end + 2) {     /* wrong endian? */
+            toy->toy_gmtbase = sim_byteswap32 (toy->toy_gmtbase);
+            toy->toy_gmtbasemsec = sim_byteswap32 (toy->toy_gmtbasemsec);
+            }
+        }
+    toy->toy_endian_plus2 = sim_end + 2;
+    todr_resync ();
+    }
 return r;
 }