diff --git a/H316/h316_lp.c b/H316/h316_lp.c
index 6f97d85c..230626de 100644
--- a/H316/h316_lp.c
+++ b/H316/h316_lp.c
@@ -97,6 +97,7 @@ int32 lpt_stopioe = 0;                                  /* stop on error */
 int32 lptio (int32 inst, int32 fnc, int32 dat, int32 dev);
 t_stat lpt_svc (UNIT *uptr);
 t_stat lpt_reset (DEVICE *dptr);
+t_stat lpt_attach (UNIT *uptr, CONST char *cptr);
 
 /* LPT data structures
 
@@ -135,7 +136,7 @@ DEVICE lpt_dev = {
     "LPT", &lpt_unit, lpt_reg, NULL,
     1, 10, 31, 1, 8, 8,
     NULL, NULL, &lpt_reset,
-    NULL, NULL, NULL,
+    NULL, &lpt_attach, NULL,
     &lpt_dib, DEV_DISABLE
     };
 
@@ -355,3 +356,11 @@ CLR_ENB (INT_LPT);
 sim_cancel (&lpt_unit);                                 /* deactivate unit */
 return SCPE_OK;
 }
+
+/* Attach routine */
+
+t_stat lpt_attach (UNIT *uptr, CONST char *cptr)
+{
+sim_switches |= SWMASK ('A');   /* Default to Append to existing file */
+return attach_unit (uptr, cptr);
+}
diff --git a/H316/h316_stddev.c b/H316/h316_stddev.c
index ffe2876a..cf519a9f 100644
--- a/H316/h316_stddev.c
+++ b/H316/h316_stddev.c
@@ -421,13 +421,16 @@ return SCPE_OK;
 t_stat pt_attach (UNIT *uptr, CONST char *cptr)
 {
 t_stat r;
+int32 saved_switches = sim_switches;
 
 if (!(uptr->flags & UNIT_ATTABLE))                      /* not tti,tto */
     return SCPE_NOFNC;
-if (strcmp ("PTR", sim_uname (uptr)) == 0)              /* PTR is read only */
-    sim_switches |= SWMASK ('R');
-if ((r = attach_unit (uptr, cptr)))
+sim_switches &= ~SWMASK ('A');
+if (strcmp ("PTP", sim_uname (uptr)) == 0)              /* PTP is append default */
+    sim_switches |= SWMASK ('A');
+if ((r = attach_unit (uptr, cptr)) != SCPE_OK)
     return r;
+sim_switches = saved_switches;
 if (sim_switches & SWMASK ('A'))                        /* -a? ASCII */
     uptr->flags |= UNIT_ASC;
 else if (sim_switches & SWMASK ('U'))                   /* -u? Unix ASCII */
diff --git a/doc/h316_doc.doc b/doc/h316_doc.doc
index ed848656..d0bdf7a4 100644
Binary files a/doc/h316_doc.doc and b/doc/h316_doc.doc differ