diff --git a/apps/pdp11/tapes/diags/README.md b/apps/pdp11/tapes/diags/README.md
index 847690503..217ce7b56 100644
--- a/apps/pdp11/tapes/diags/README.md
+++ b/apps/pdp11/tapes/diags/README.md
@@ -10,7 +10,7 @@ Diagnostic Paper Tape Images
 Thanks to the [iamvirtual.ca](http://iamvirtual.ca/collection/systems/mediadoc/mediadoc.html#papertape)
 website, we have archived the PDP-11 diagnostics shown below.  The tapes have been added to the
 [Default PC11 Configuration](/devices/pdp11/pc11/), so that you can easily load them into any machine with a
-[PC11](/modules/pdp11/lib/pc11.js), such as this [PDP-11/20](/devices/pdp11/machine/1120/panel/debugger/).
+[PC11](/modules/pdp11/lib/pc11.js), such as this [PDP-11/20 with Front Panel and Debugger](/devices/pdp11/machine/1120/panel/debugger/).
 
 As noted for other [DEC PDP-11 Tape Images](/apps/pdp11/tapes/), these "Absolute Format" tapes can be loaded directly
 into RAM using the machine's "Load" button instead of "Attach", allowing you to bypass the usual three-step process of
@@ -176,6 +176,9 @@ it expects the MUL instruction to trap.
 
 ### Test 15
 
+Before loading and running this test on the [PDP-11/20 with Front Panel and Debugger](/devices/pdp11/machine/1120/panel/debugger/),
+it's recommended that you also toggle SW-15, as described below, so that the test will HALT on any failure.
+
 	MAINDEC-11-D0OA (NEW NUMBER - DZQKA)
 	
 	T15 Instruction Exerciser
diff --git a/devices/pdp11/pc11/default.xml b/devices/pdp11/pc11/default.xml
index ffd229b83..3375dabc7 100644
--- a/devices/pdp11/pc11/default.xml
+++ b/devices/pdp11/pc11/default.xml
@@ -47,7 +47,7 @@
 			<tape id="diags.tape14b" name="MD-11 TEST 14B - TRAP TEST" path="/apps/pdp11/tapes/diags/MAINDEC-11-D0NB-PB.json"/>
 			<tape id="diags.tape14c" name="MD-11 TEST 14C - TRAP TEST" path="/apps/pdp11/tapes/diags/MAINDEC-11-D0NC-PB.json"/>
 			<tape id="diags.tape15" name="MD-11 TEST 15 - CPU EXERCISER" path="/apps/pdp11/tapes/diags/MAINDEC-11-D0OA-PB.json"/>
-			<tape id="tray02.tape04" name="11/70 CPU EXERCISER" path="/apps/pdp11/tapes/diags/MAINDEC-11-DEQKC-B1-PB.json"/>
+			<tape id="tray02.tape04" name="MD-11 11/70 CPU EXERCISER" path="/apps/pdp11/tapes/diags/MAINDEC-11-DEQKC-B1-PB.json"/>
 		</control>
 		<control type="button" binding="attachTape">Attach</control>
 		<control type="button" binding="loadTape">Load</control>
diff --git a/modules/pdp11/lib/serialport.js b/modules/pdp11/lib/serialport.js
index 7ca259d5f..c1cb55e01 100644
--- a/modules/pdp11/lib/serialport.js
+++ b/modules/pdp11/lib/serialport.js
@@ -543,6 +543,11 @@ SerialPortPDP11.prototype.transmitByte = function(b)
         }
     }
 
+    /*
+     * TODO: Why do DEC diagnostics like to output bytes with bit 7 set?
+     */
+    b &= 0x7F;
+
     if (this.controlIOBuffer) {
         if (b == 0x0D) {
             this.iLogicalCol = 0;
diff --git a/modules/shared/lib/strlib.js b/modules/shared/lib/strlib.js
index 2abaf3fa8..f0509b825 100644
--- a/modules/shared/lib/strlib.js
+++ b/modules/shared/lib/strlib.js
@@ -565,7 +565,7 @@ str.aASCIICodes = {
  // 0x0A:   "LF",       // (CTRL_J) Line Feed (New Line)
     0x0B:   "VT",       // (CTRL_K) Vertical Tab
     0x0C:   "FF",       // (CTRL_L) Form Feed (New Page)
-    0x0D:   "CR",       // (CTRL_M) Carriage Return
+//  0x0D:   "CR",       // (CTRL_M) Carriage Return
     0x0E:   "SO",       // (CTRL_N) Shift Out
     0x0F:   "SI",       // (CTRL_O) Shift In
     0x10:   "DLE",      // (CTRL_P) Data Link Escape