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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.