CDM-750 Advanced High-Speed Trunking Modem
Rear Panel Connections
3.2.2.2
J2 | REDUNDANCY Connector, DB-9F
Fault/Clock signal to signal the switch when a fault occurs. It is intended only for connection to a
CRS‐170A or CRS‐180 1:1 Redundancy Switch.
The connector pinouts are as follows:
Pin #
Name
5 MDM_COM_OUT_ENA
9
12VOLT_OUT
4 ONLINE
8
SER_DATA
3 TX_IF_MUTE_B
7
SER_CLK
2 MDM_COM_IN
6
MDM_COM_OUT
1 GND
3.2.2.3
J3 | REMOTE Connector, DB-9M
The connector pinouts are as follows:
Pin #
1 Ground
6
EIA-485 Receive Data B *
2 EIA-232 Transmit Data
7
EIA-485 Receive Data A *
3 EIA-232 Receive Data
8
EIA-485 Transmit Data B
4 Reserved - do not connect to this pin
9
EIA-485 Transmit Data A
5 Ground
* Use for 2-wire EIA-485 operation
The 9‐pin Type 'D' female (DB‐9F) J2 | REDUNDANCY connector provides the
1:1 control interface. It provides serial communications to transfer
configuration information from the Prime to the Backup modem, and a
Signal Function
Enable "Mdm_Comm_Out" signal
+12 Volts at 300 ma
Commands modem to be Online/Offline
(Use pull-up on Modem side input)
Fault Serial Data Signal from modem
Capability to mute modem's Tx IF (Low=Mute)
(Use pull-up on Modem side input)
Fault Serial Clock Signal 64KHz
UART comm to modem from controller
(9600 to115.2BUAD)
UART comm. from modem to controller
(9600 to115.2BUAD)
Chassis Ground
The 9‐pin Type 'D' male (DB‐9M) J3 | REMOTE connector provides the remote
control interface via an M&C computer or terminal device. It is user selectable
for either EIA‐232 or EIA‐485.
Description
Direction (I/O)
–
I
O
I
I
O
–
O
–
3–9
Revision 2
MN-CDM750
Singal Type
LVTTL Output
12V 300 ma
LVTTL Input
LVTTL Output
LVTTL Input
LVTTL Output
LVTTL Input
LVTTL Output
Gnd
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