diff --git a/patches/dmcstart.cmd b/patches/dmcstart.cmd
index 2eb4418..f823e5e 100644
--- a/patches/dmcstart.cmd
+++ b/patches/dmcstart.cmd
@@ -1,7 +1,7 @@
-; Fix DMC startup problem (buffers assigned before startup done)
-; in RSTS 9.2.  (This bug was fixed in RSTS 9.3.)
-;
-; This is a Monitor patch
+! Fix DMC startup problem (buffers assigned before startup done)
+! in RSTS 9.2.  (This bug was fixed in RSTS 9.3.)
+!
+! This is a Monitor patch
 File to patch? <LF>
 Module name? XVR
 Base address? XMDVRM
diff --git a/patches/dmrtbl.cmd b/patches/dmrtbl.cmd
index 99d4fd3..d1380f3 100644
--- a/patches/dmrtbl.cmd
+++ b/patches/dmrtbl.cmd
@@ -1,10 +1,10 @@
-; Patch to fix incorrect display of DMR line card configuration
-; in HARDWARE LIST option.
-;
-; This patch is for RSTS 10.1.
-;
-; Paul Koning, 19-Aug-2016
-;
+! Patch to fix incorrect display of DMR line card configuration
+! in HARDWARE LIST option.
+!
+! This patch is for RSTS 10.1.
+!
+! Paul Koning, 19-Aug-2016
+!
 File to patch? INIT.SYS
 Base address? HAR
 Offset address? 6166
diff --git a/patches/hello.cmd b/patches/hello.cmd
index acc1f66..49d184c 100644
--- a/patches/hello.cmd
+++ b/patches/hello.cmd
@@ -1,8 +1,8 @@
-; Fix invalid address in point to point hello messages introduced
-; in RSTS 9.6 (or possibly earlier), DECnet/E V4.x.
-;
-; This is a Monitor patch
-;
+! Fix invalid address in point to point hello messages introduced
+! in RSTS 9.6 (or possibly earlier), DECnet/E V4.x.
+!
+! This is a Monitor patch
+!
 File to patch? <LF>
 Enter the name of the module in the SIL to be patched: TRN
 Base address? ROUDDC@OVR
diff --git a/patches/kdj11e.cmd b/patches/kdj11e.cmd
new file mode 100644
index 0000000..7edf145
--- /dev/null
+++ b/patches/kdj11e.cmd
@@ -0,0 +1,25 @@
+! Fix line frequency autoconfiguration on SIMH
+! This corrects an unsigned arithmetic error that appears on SIMH
+! due to its much higher instruction execution rate.
+!
+! This patch is for RSTS/E V10.1
+!
+! Paul Koning 14-Sep-20
+!
+File to patch? [0,1]INIT.SYS
+Base address? SATBUF
+Offset address? 3756
+ Base	Offset  Old     New?
+??????	003756	072327	? 4737
+??????	003760	177774	? PATCH
+??????	003762	020403	? ^Z
+Offset address? ^Z
+Base address? PATCH
+Offset address? 0
+ Base	Offset  Old     New?
+??????	000000	000000	? CLC
+??????	000002	000000	? ROR+3
+??????	000004	000000	? 72327
+??????	000006	000000	? -3
+??????	000010	000000	? 207
+??????	000012	??????	? ^C