Comtech EF Data CRS-300 - Manual (Page 250)

CRS-300 1:10 Redundancy Switch MN/CRS300.IOM
Appendix B Revision 19
B-4
B.2.3 Switch-to-User, Monitor and Control (M&C) Cable (DB-9FDB-9F)
You may use this cable for a simple EIA-232 connection between the Switch “Remote Control” connector and a PC serial port. You will
need this cable for Switch M&C purposes and to perform your modem’s firmware update procedure.
Figure B-3. Switch and Modem M&C Cable