Efbus1/2 port (external), Monitor and control, 3 efbus1/2 port (external) – Comtech EF Data SNM-1000 User Manual
Page 122: 4 monitor and control
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SNM-1000 Node Control Modem
Revision 3
Theory of Operation
MN/SNM1000.IOM
4–4
4.1.3
EFBUS1/2 Port (External)
The EFBUS 1/2 port combines EFBUS1 and EFBUS2 onto a common connector at J6, a
10-pin header.
The EFBUS port provides two separate 2-wire EIA-485 interfaces wired to
a common 9-pin D female connector located on the rear of the MIDAS modem.
The IF
Modulator and IF Demodulator status is also presented for external use.
The Modem Control serial port, EFBUS1, is used for control of other Comtech EF Data
traffic modems.
The signals are described in the following table with signal names having
the MC prefix.
The interface is ASYNC, EIA-485/2-wire, and 19.2 kbps.
The EFBUS2 port is reserved for communication with future MIDAS traffic modems.
Signal Function
Name
I/O
J6 EFBUS
10-Pin
Header
J2 VFDU
Interface
96-Pin
MIDAS
Conn
Pin #
Signal
Level
Ground MCGND
-
1
NC
1
-
Demodulator fault
BP_DF
I/O
3
NC
2
TTL
Modulator fault
BP_MF
I/O
5
NC
3
TTL
Receive/Transmit +
MS_RD/SD+(EFBUS2)
I/O
7
B14
4
EIA-485
Receive/Transmit -
MS_RD/SD-(EFBUS2)
I/O
9
C14
5
EIA-485
Receive/Transmit+ MC_RD/SD+(EFBUS1)
I/O
2
NC
6 EIA-485
Receive/Transmit- MC_RD/SD-(EFBUS1)
I/O 4
NC
7 EIA-485
Ground MSGND
-
6
8
-
Not used
-
-
8
9
-
Not used
-
-
10
-
-
4.1.4
Monitor and Control
The modem uses a sophisticated microcontroller module to perform M&C functions. This
module is located on the demodulator board. The M&C monitors the modem and
provides configuration updates to other modules within the modem as required.
The modem configuration parameters are maintained in battery-backed RAM. The RAM
provides for total recovery after a power-down situation.
Notes:
1. Extensive fault monitoring and status gathering are provided.
2. Modem functions are accessible through a user port interface.