diff --git a/README.md b/README.md
index ec73357..e00154d 100644
--- a/README.md
+++ b/README.md
@@ -166,6 +166,7 @@ Documentation
 -------------
 
 * [TWI Cable Assembly Notes (AC100, AC101)](doc/TWI_CABLE_ASSY_NOTES.md)
+* [MX Connector Modification Notes (AC101)](doc/MX_CONN_MOD_NOTES.md)
 
 Contributors
 ------------
diff --git a/doc/MX_CONN_MOD_NOTES.md b/doc/MX_CONN_MOD_NOTES.md
new file mode 100644
index 0000000..90221fe
--- /dev/null
+++ b/doc/MX_CONN_MOD_NOTES.md
@@ -0,0 +1,19 @@
+MX Connector
+------------
+
+![pinout](pic/mx_female_receptacle_pinout.png)
+
+View (note vertically offset center keying peg location):
+
+* Female receptacle viewed from mating face
+* Male plug solder cups viewed from assembly face
+
+Pinout map:
+
+* Hirose Pin 2 (GRN) - MX Pin 8 (DATA)
+* Hirose Pin 3 (YEL) - MX Pin 10 (SENSE)
+* Hirose Pin 4 (BLK) - MX Pin 9 (GND)
+
+Hirose pins 1, 5, and 6 should NOT be connected to anything (leave floating)
+
+Do not attach both the MX connector to a keyloader and the Hirose connector to the KFDtool at the same time. It will not damage anything, however, keyload operations may fail.
diff --git a/doc/pic/mx_female_receptacle_pinout.png b/doc/pic/mx_female_receptacle_pinout.png
new file mode 100644
index 0000000..aa3a579
Binary files /dev/null and b/doc/pic/mx_female_receptacle_pinout.png differ