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Remote interface specification, M&c theory of operation, Remote interface configuration – Comtech EF Data SNM-1001 User Manual

Page 41: Modem defaults, 2 remote interface specification, 3 m&c theory of operation, 4 remote interface configuration, 5 modem defaults

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Theory of Operation

SNM-1001 Network Control Modem

4–10

Rev. 1

4.3.2

Remote Interface Specification

Refer to Appendix A for the remote interface specification.

4.3.3

M&C Theory of Operation

The M&C module is built around the Intel 80C32 micro-controller, operating at
11.0592 MHz. The microsystem is designed to support up to 512 kbytes of read-only
code memory, and up to 32 kbytes of non-volatile random-access data memory.

4.3.4

Remote Interface Configuration

All modem functions can be remotely controlled and monitored via an EIA-232-C
communications link. The EIA-232-C interface is used to communicate with a single
modem.

For M&C jumper settings, refer to Table 4-1.

4.3.5 Modem

Defaults

The M&C has default settings that are loaded into the modem at power-up. These default
settings are also loaded each time the modem has been hard reset. The following tables
list the defaults settings for each modem configuration parameter.

Defaults for Burst Mode

Modulator Defaults

Demodulator Defaults

Data Rate

A

Data Rate

A

TX Rate A

19.2 kbit/s, QPSK

RX Rate A

19.2 kbit/s, QPSK

TX-IF Frequency

70 MHz

RX-IF Frequency

70 MHz

TX-IF Output

ON

Descrambler

ON

Mod Power Offset

0 dB

Differential Decoder

OFF

TX Power Output

-10 dBm

Demodulator Type

INTELSAT Open

Scrambler

ON

Decoder Type

Viterbi, 1/2 Rate

Differential Encoder

OFF

IF Loopback

OFF

Modulator Type

INTELSAT Open

RF Loopback

OFF

Encoder Type

Viterbi, 1/2 Rate

BER Threshold

None

CW Mode

Normal (OFF)

Interface Defaults

System Defaults

TX Clock Source

TX TERRESTRIAL

Time

12:00 AM

TX Clock Phase

NORMAL

Date

7/4/76

RX Clock Phase

NORMAL

Baud Rate

9600

Baseband Loopback

OFF

Parity

Even

Address

1

Operation Mode

Duplex