Comtech EF Data SDM-300A User Manual
Page 85
![background image](/files/778893/content/doc085.png)
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.