Functional Description Of Async Overhead Channel Unit; Terrestrial Interface - Comtech EF Data SDM-650B Installation And Operation Manual

Asynchronous Overhead Channel Unit
F.1 Functional Description of ASYNC Overhead Channel Unit
The ASYNC overhead interface module consists of three subassemblies:
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The connector board provides the physical interface utilizing a 50-pin D connector. The
terrestrial interface contains all circuitry required for G.703, RS-422, MIL-STD-188, and
V.35 type interfaces for synchronous data. The terrestrial interface also contains circuitry
for RS-232-C and RS-485 type interfaces for ASYNC data.
The data processor contains all circuitry required for:
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Refer to Figure F-1 for a block diagram of the ASYNC overhead interface.
F–2
Connector board (AS/1328)
Terrestrial interface (AS/1311)
Data processor board (AS/1289)
Multiplexing the synchronous and ASYNC data streams
Data rate synthesizers
Optional plesiochronous buffer
SDM-650B Satellite Modem
Rev. 5