diff --git a/PDP11/pdp11_dmc.c b/PDP11/pdp11_dmc.c
index 653ed6b0..c3d29af9 100644
--- a/PDP11/pdp11_dmc.c
+++ b/PDP11/pdp11_dmc.c
@@ -3714,7 +3714,6 @@ if (!(dptr->flags & DEV_DIS)) {
             dmc_process_master_clear(controller);
             }
         }
-    sim_activate_after (dptr->units+dptr->numunits-2, DMC_CONNECT_POLL*1000000);/* start poll */
     }
 
 return ans;
@@ -3767,8 +3766,10 @@ uptr->flags &= ~UNIT_ATT;
 for (i=attached=0; i<mp->lines; i++)
     if (dptr->units[i].flags & UNIT_ATT)
         ++attached;
-if (!attached)
+if (!attached) {
     sim_cancel (dptr->units+mp->lines);              /* stop poll on last detach */
+    sim_cancel (dptr->units+(mp->lines+1));          /* stop timer on last detach */
+    }
 free (uptr->filename);
 uptr->filename = NULL;
 return tmxr_detach_ln (lp);
diff --git a/PDP11/pdp11_dup.c b/PDP11/pdp11_dup.c
index 3aa22b90..eaf98b0b 100644
--- a/PDP11/pdp11_dup.c
+++ b/PDP11/pdp11_dup.c
@@ -1237,8 +1237,6 @@ dup_desc.dptr = DUPDPTR;                                /* Connect appropriate d
 dup_desc.uptr = dup_units+dup_desc.lines;               /* Identify polling unit */
 sim_cancel (dup_units+dup_desc.lines);                  /* stop poll */
 ndev = ((dptr->flags & DEV_DIS)? 0: dup_desc.lines );
-if (ndev)
-    sim_activate_after (dup_units+dup_desc.lines, DUP_CONNECT_POLL*1000000);
 return auto_config (dptr->name, ndev);                  /* auto config */
 }