diff --git a/build/misc.tcl b/build/misc.tcl
index 683cc38e..b16cbd76 100644
--- a/build/misc.tcl
+++ b/build/misc.tcl
@@ -452,6 +452,11 @@ respond "*" ":link sys;ts mailt,sys2;ts emacs\r"
 
 # rmtdev
 respond "*" ":midas device;atsign rmtdev_gz;rmtdev\r"
+expect ":KILL"
+
+# mmodem
+respond "*" ":midas sys3; ts mmodem_gz; mmodem\r"
+expect ":KILL"
 
 # Compile ADVENT and dump it out with DECUUO.
 respond "*" ":cwd games\r"
diff --git a/build/timestamps.txt b/build/timestamps.txt
index 29e2aab3..92774af2 100644
--- a/build/timestamps.txt
+++ b/build/timestamps.txt
@@ -665,6 +665,7 @@ gsb/ttyvar.17 197801021617.41
 gt40/bootvt.s09 197202050000.00
 gt40/vt07.bin29 197508150459.59
 gz/macn80.mid 198305040113.01
+gz/mmodem.181 198511261837.46
 humor/alices.pdp10 198505170252.01
 humor/dover.poem 198106270542.08
 humor/jargon.68 198308110614.15
@@ -771,6 +772,7 @@ _info_/meter.info 197501110133.04
 info/micros.9 198509132154.55
 info/midas.archiv 197811170857.23
 _info_/migs.order 197610292236.59
+_info_/mmodem.order 198309251915.04
 _info_/muscom.order 197610050148.10
 _info_/musrun.order 197610050143.17
 _info_/name.info 197503250817.09
diff --git a/doc/_info_/mmodem.order b/doc/_info_/mmodem.order
new file mode 100755
index 00000000..65e424ad
--- /dev/null
+++ b/doc/_info_/mmodem.order
@@ -0,0 +1,27 @@
+MMODEM is the ITS companion to the CP/M 'MODEM' file transfer program.
+ 
+Usage:
+:MMODEM xx filename
+ 
+where xx is one of:
+S - send file.  MMODEM figures out whether it is an ascii or a COM file
+SA - send ascii file
+SC - send COM file
+SH - send HEX file. The file is 'comified' in core before being sent
+SM - send MACN80 output file. The file is 'comified' in core before being sent
+R - receive file.  MMODEM guesses format (ascii/COM) by file type, or asks you
+RA - receive ascii file
+RC - receive COM file
+RZ - receive ascii file containing ^Z's. Normally ^Z is treated as end of file
+     With this option, only trailing ^Zs are ignored.
+RAC,RCC,RZC - like RA,RC,RZ but using CRC's instead of checksums.
+ 
+Also available:
+SB - send random binary file (4 8-bit bytes per PDP-10 word, left-justified).
+RB - receive random binary file.
+RBC - receive random binary file using CRC's instead of checksums.
+Note that the non-ascii files on the CPM; directory are *not* random binary
+files, they are COM files.  Use SC/RC for those.
+ 
+Mail bugs, questions, feature requests to BUG-MMODEM@MC.
+ 
diff --git a/doc/programs.md b/doc/programs.md
index 114d95ac..08a3d60b 100644
--- a/doc/programs.md
+++ b/doc/programs.md
@@ -227,6 +227,7 @@
 - MINSKY TRON, display hack translated from the PDP-1.
 - MLDEV/MLSLV, allows access to remote systems as devices (e.g. DB:).
 - MLIFE, Mike Speciner's Conway Life.
+- MMODEM, Xmodem file transfer.
 - MODEMS, modems dragon.
 - MONIT, lightweight ATSIGN HACTRN replacement without debugging support.
 - MSEND, send to many users.
diff --git a/src/gz/mmodem.181 b/src/gz/mmodem.181
new file mode 100644
index 00000000..f7b49ab7
Binary files /dev/null and b/src/gz/mmodem.181 differ