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Sms-451e description, 2 sms-451e description – Comtech EF Data SMS-451 User Manual

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SMS-451 Sateliite Switch

Revision 0

Introduction

MN/SMS451.IOM

1–5

1.1.2 SMS-451E

Description

MANUAL

AUTO

ON-LINE

FAULT

MODULATOR

A

A

A

B

B

B

MANUAL

AUTO

ON-LINE

FAULT

DEMODULATOR

A

A

A

B

B

B

REM O T E

R E M

L O C A L

P W R 1

P W R 2

SWITCH STATUS

L O C

SMS-451E ECL MODEM
PROTECTION SWITCH

Figure 1-4. SMS-451E


The SMS-451E 1:1 ECL Modem Protection Switch (Figure 1-4) is a fully automated 1:1
ECL protection switch for the Comtech EF Data SDM-9000 satellite modem.

IMPORTANT

ECL/HSSI connection also is available for the SDM-2020 Modems.


The switch is used to protect SDM-9000 modems using an ECL, Positive Emitter
Coupled Logic (PECL), or MIL-STD-188 terrestrial interface. The switch provides
redundancy for one prime modem with one backup modem.

The switch contains circuitry for:

• Data and IF switching
• Remote and local status reporting
• Remote and local control


The switch can be supplied with any of the following baseband interfaces:

• ECL
• PECL (positive level ECL)
• MIL-STD-188


The switch top assembly has the following configurations:

Operation

Input

Frequency

Interface

Modem
(Dependent)

AC 75

70 ECL

Mod/Demod
(Independent)

AC 50

140 PECL

DC 50

188

DC 75