diff --git a/imlac/imlac_cpu.c b/imlac/imlac_cpu.c
index 13c49138..5fced6c9 100644
--- a/imlac/imlac_cpu.c
+++ b/imlac/imlac_cpu.c
@@ -506,6 +506,12 @@ flag_off (uint16 flag)
   sim_debug (DBG_IRQ, &irq_dev, "Flag off %06o -> %06o\n", flag, FLAGS);
 }
 
+uint16
+flag_check (uint16 flag)
+{
+  return FLAGS & flag;
+}
+
 static uint16
 irq_iot (uint16 insn, uint16 AC)
 {
diff --git a/imlac/imlac_defs.h b/imlac/imlac_defs.h
index db3ccc2c..ecf9bab9 100644
--- a/imlac/imlac_defs.h
+++ b/imlac/imlac_defs.h
@@ -56,6 +56,7 @@ typedef struct {
 extern t_bool build_dev_tab (void);
 extern void flag_on (uint16 flag);
 extern void flag_off (uint16 flag);
+extern uint16 flag_check (uint16 flag);
 extern void dp_on (int flag);
 extern uint16 dp_is_on (void);
 extern void crt_point (uint16 x, uint16 y);
diff --git a/imlac/imlac_pt.c b/imlac/imlac_pt.c
index da0742c5..dcf23d51 100644
--- a/imlac/imlac_pt.c
+++ b/imlac/imlac_pt.c
@@ -26,10 +26,17 @@
 
 #include "imlac_defs.h"
 
+/* Debug */
+#define DBG             0001
+
 /* Function declaration. */
+static t_stat ptr_svc (UNIT *uptr);
 static uint16 ptr_iot (uint16, uint16);
 static uint16 ptp_iot (uint16, uint16);
 static t_stat ptr_boot (int32 u, DEVICE *dptr);
+static t_stat ptr_detach (UNIT *uptr);
+
+static uint16 PTRB;
 
 static uint16 ptr_rom[] = {
   0060077, 0020010, 0104076, 0020020, 0001061, 0100011, 0002400, 0010046,
@@ -38,18 +45,32 @@ static uint16 ptr_rom[] = {
   0010067, 0100011, 0030020, 0010053, 0110076, 0000002, 0037700, 0037677,
 };
 
+static UNIT ptr_unit = {
+  UDATA (&ptr_svc, UNIT_IDLE+UNIT_ATTABLE, 0)
+};
+
+static REG ptr_reg[] = {
+  { ORDATAD (PTRB, PTRB, 8, "Receive buffer") },
+  { NULL }
+};
+
 static IMDEV ptr_imdev = {
   2,
   { { 0005, ptr_iot, { NULL, "HRB", "HOF", NULL } },
     { 0006, ptr_iot, { NULL, "HON", "STB", NULL } } }
 };
 
+static DEBTAB ptr_deb[] = {
+  { "DBG", DBG },
+  { NULL, 0 }
+};
+
 DEVICE ptr_dev = {
-  "PTR", NULL, NULL, NULL,
-  0, 8, 16, 1, 8, 16,
+  "PTR", &ptr_unit, ptr_reg, NULL,
+  1, 8, 16, 1, 8, 16,
   NULL, NULL, NULL,
-  &ptr_boot, NULL, NULL,
-  &ptr_imdev, DEV_DISABLE | DEV_DEBUG | DEV_DIS, 0, NULL,
+  &ptr_boot, &attach_unit, &ptr_detach,
+  &ptr_imdev, DEV_DISABLE | DEV_DEBUG | DEV_DIS, 0, ptr_deb,
   NULL, NULL, NULL, NULL, NULL, NULL
 };
 
@@ -67,17 +88,50 @@ DEVICE ptp_dev = {
   NULL, NULL, NULL, NULL, NULL, NULL
 };
 
+static t_stat
+ptr_svc (UNIT *uptr)
+{
+  unsigned char ch;
+  uint16 flag;
+
+  /* This function is called when the motor is on.  The data ready
+     flag toggles on and off when the tape goes past the read head. */
+
+  if (flag_check (FLAG_PTR)) {
+    flag_off (FLAG_PTR);
+  } else {
+    if (sim_fread (&ch, 1, 1, uptr->fileref) == 1) {
+      sim_debug (DBG, &ptr_dev, "Received character %03o\n", ch);
+      PTRB = ch;
+      flag_on (FLAG_PTR);
+    } else {
+      sim_debug (DBG, &ptr_dev, "No more data\n");
+      return SCPE_OK;
+    }
+  }
+
+  sim_activate_after (uptr, 1000);
+  return SCPE_OK;
+}
+
 static uint16
 ptr_iot (uint16 insn, uint16 AC)
 {
   if ((insn & 0771) == 0051) { /* HRB */
-    AC |= 0;
+    sim_debug (DBG, &ptr_dev, "Read character %03o\n", PTRB);
+    AC |= PTRB;
   }
   if ((insn & 0772) == 0052) { /* HOF */
-    ;
+    flag_off (FLAG_PTR);
+    if (sim_is_active (&ptr_unit))
+      sim_cancel (&ptr_unit);
+    sim_debug (DBG, &ptr_dev, "Motor off.\n");
   }
   if ((insn & 0771) == 0061) { /* HON */
-    ;
+    flag_off (FLAG_PTR);
+    if (ptr_unit.flags & UNIT_ATT)
+      sim_activate_after (&ptr_unit, 1000);
+    sim_debug (DBG, &ptr_dev, "Motor on.\n");
   }
   if ((insn & 0772) == 0062) { /* STB */
     ;
@@ -111,3 +165,13 @@ ptr_boot (int32 u, DEVICE *dptr)
   *PC = 040;
   return SCPE_OK;
 }
+
+static t_stat
+ptr_detach (UNIT *uptr)
+{
+  if (!(uptr->flags & UNIT_ATT))
+    return SCPE_OK;
+  if (sim_is_active (uptr))
+    sim_cancel (uptr);
+  return detach_unit (uptr);
+}