Appendix F - Pin Descriptions
63
Multi-Tech Systems, Inc. MT5600BA/BL Series User Guide
RDL 21 RDL Remote Digital Loop Input to modem to enable RDL test.
RI 22 Ring Indicator RI output high indicates the presence of
a ring signal on the telephone line.
23 NC
XCLK 24 XCLK External Clock Input to modem used in special syn-
chronous applications.
TM 25 TM Test Mode Output from modem to indicate modem is in
one of the test modes.
RJ-11Modular PlugTo TerminalBlock Screws
2345
2345

Red (Tip)

Green (Ring)

Fig. F-1. 25-pin to 25-pin RS-232 cable.
20 DTR
22 RI
8CD
7 GND
6 DSR
5 CTS
4 RTS
3RD
2TD
DCE DB-25
connector
DTE DB-9
connector
DTR 4
RI 9
CD 1
GND 5
DSR 6
CTS 8
RTS 7
RD 2
TD 3
Fig. F-2. 9-pin to 25-pin RS-232 cable.
Label Pin I/O type Signal name/description