From c9dae318dfdbf728f66a7c6cd05091ceafea398b Mon Sep 17 00:00:00 2001
From: Mark Pizzolato <mark@infocomm.com>
Date: Tue, 19 Jun 2018 23:58:22 -0700
Subject: [PATCH] SCP: Avoid need for TMXR devices to have dummy DEVICE examine
 and deposit values

---
 scp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/scp.c b/scp.c
index 632927b1..9f1729a5 100644
--- a/scp.c
+++ b/scp.c
@@ -8419,7 +8419,8 @@ for (i = 0, j = addr; i < sim_emax; i++, j = j + dptr->aincr) {
     else {
         if (!(uptr->flags & UNIT_ATT))
             return SCPE_UNATT;
-        if (uptr->dynflags & UNIT_NO_FIO)
+        if ((uptr->dynflags & UNIT_NO_FIO) ||
+            (uptr->fileref == NULL))
             return SCPE_NOFNC;
         if ((uptr->flags & UNIT_FIX) && (j >= uptr->capac)) {
             reason = SCPE_NXM;