Comtech EF Data SDM-300A - Manual (Page 85)

SDM-300A Satellite Modem Revision 6
External Connections MN/SDM300A.IOM
4–7
Table 4-4. 25-Pin D Connector Pinouts
25-Pin D Connector
Pin # RS-422 RS-232 V.35
1 SHLD SHLD SHLD
2 SD-A TXD SD-A
3 RD-A RXD RD-A
4 RS-A RTS RTS
5 CS-A CTS CTS
6 DM-A DSR DSR
7 SIGGND SIGGND SIGGND
8 RR-A
DCD RLSD
9 RT+B SCR+B
10 RR-B
11 TT+B SCTE+B
12 ST+B SCT+B
13 CS+B
14 SD+B SD+B
15 ST-A ST SCT-A
16 RD+B RD+B
17 RT-A RXC SCR-A
18 LL LL LL
19 RS+B
20* MC-A MC MC-A
21 DF DF DF
22 DM+B
23* MC+B MC+B
24 TT-A TXC SCTE-A
25 MF MF MF
*Note: Use the MASTER clock for EXTERNAL clock input. This clock input should
equal the data rate unless the Asymmetrical Loop Timing Option (ASLT) is available.
The ASLT option allows selection of different clock rates that vary from the digital data
rate. Refer to the Utility: Modem Type: Modem Options menu for the ASLT option
information.