
DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem
Electrical Interfaces
TM065 - Rev. 3.3
5-3
Table 5-2. RS-232 Terminal Port – 9-Pin Female “D” Connector (J5)
Pin Number
Signal
Description
Direction
2
TxD
Transmit Data
Input
3
RxD
Receive Data
Output
5
GND
Ground
–
5.3.6 ALARM (J6)
The modem has two Form-C Dry Contact Alarm Relays onboard and an Alarm Connector located
on the rear panel, the 9-pin male “D” sub connector (J6).
The two relays are designated Modulator Alarm and Demodulator Alarm. Non-Alarm is defined as
the powered state of the relay. Thus, if there is a Modulator Alarm and/or Demodulator Alarm, the
pins will be connected as shown in Table 5-3:
Table 5-3. Alarm Relays
Alarm
No Alarm
Modulator
Pins 2 and 3 Shorted
Pins 1 and 2 Shorted
Demodulator
Pins 8 and 9 Shorted
Pin 7 and 8 Shorted
The pin definitions for J6 are shown in Table 5-4 below.
Note: The NC and NO (Normally Closed and Normally Open) nomenclature applies to non-
energized relays.
Table 5-4. Alarm Connector Pin Assignment (J6)
J6 Pin
Number
Connection
1
Mod Alarm Relay A NO on Alarm
2
Mod Alarm Relay A Common
3
Mod Alarm Relay A NC on Alarm
4
5
AGC Voltage Output
6
GND
7
Demod Alarm Relay B NO on Alarm
8
Demod Alarm Relay B Common
9
Demod Alarm Relay B NC on Alarm
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