Comtech EF Data CDM-570A - Manual (Page 69)

CDM-570A/570AL Satellite Modem with Optional Packet Processor MN-CDM570A
Rear Panel Connectors and Pinouts Revision 2
3–7
3.2.2 Terrestrial Data Connections Group
3.2.2.1 Data Interface Connector, DB-25F
This 25-pin ‘D’ type female (DB-25F) Data Interface connector
conducts data input and output breakout panel switching protection.
This connector conforms to the EIA-530 pinout, which allows for
connection of different electrical standards, including EIA-422, V.35,
and EIA-232. Shielded connectors resolve EMC problems unlike sometimes-used V.35
Winchester connectors.
THE MODEM IS ALWAYS ASSUMED TO BE DCE
Table 3-2. Data Interface Connector Pin Assignments
Pin #
Generic Signal
Description
Direction
EIA-422
EIA-530
V.35 EIA-232 Circuit #
2 Transmit Data A DTE to Modem SD A SD A BA 103
14 Transmit Data B DTE to Modem SD B SD B - 103
24 Transmit Clock A DTE to Modem TT A SCTE A DA 113
11 Transmit Clock B DTE to Modem TT B SCTE B - 113
15 Internal Tx Clock A Modem to DTE ST A SCT A DB 114
12 Internal Tx Clock B Modem to DTE ST B SCT B - 114
3 Receive Data A Modem to DTE RD A RD A BB 104
16 Receive Data B Modem to DTE RD B RD B - 104
17 Receive Clock A Modem to DTE RT A SCR A DD 115
9 Receive Clock B Modem to DTE RT B SCR B - 115
8 Receiver Ready A Modem to DTE RR A RLSD CF 109
10 Receiver Ready B Modem to DTE RR B - - 109
5 Clear to Send A * Modem to DTE CS A CTS CB 106
13 Clear to Send B * Modem to DTE CS B - - 106
4 Request to Send A * DTE to Modem RS A RTS CA 105
19 Request to Send B * DTE to Modem RS B - - 105
6 Data Set Ready A * Modem to DTE DM A DSR CC 107
22 Data Set Ready B * Modem to DTE DM B - - 107
7 Signal Ground - SG SG AB 102
1 Shield - Shield FG AN 101
1) This table is ordered by “Generic Signal Description” and not by connector pin orientation.
2) When the rear-panel switch marked “1:N Switch” is in the OFF position, all of the signals shown above
are available and functional. In addition, pins not shown are not connected, and therefore no damage
will occur if other signals are connected to the additional pins.
3) When the rear-panel switch marked “1:N Switch” is in the ON position, the highlighted signals, plus pins
18, 20, 21, 22, 23 and 25 are reserved for use by the 1:N system. DO NOT connect signals to any of
these pins in this mode. Certain pins have DC voltages present that may damage equipment other than
a Comtech EF Data redundancy switch.
4) For X.21 operation, use the EIA-422 pins, but ignore Receive Clock if the Modem is DTE, and ignore
Transmit Clocks if the Modem is DCE.