Receive doppler/plesiochronous buffer size, Buffer centering, Switch faults – Comtech EF Data SDM-300A User Manual

Page 383: Terrestrial interface types, Universal

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SDM-300A Satellite Modem

Revision 6

Specifications

MN/SDM300A.IOM

19–27

19.8.2.12 Receive

Doppler/Plesiochronous Buffer Size

The RX Doppler buffer size can be set by the operator from:

• Bypass.

• 32 to 262,144 bits, in 16 bit steps.

• Selectable in ms, from 2 to 98 in 2 ms steps, based on the data rate.
• Selectable Frame Format G.704 or None.

19.8.2.13 Buffer

Centering

The operator can set the buffer to 50% .The modem will automatically set the buffer to 50%
after receive signal acquisition or a buffer overflow/underflow.

19.8.2.14 Switch

Faults

Modulator Fault

Open collector output, 15V maximum, 20 mA maximum current

sink, fault is open circuit.

Demodulator Fault

Open collector output, 15V maximum, 20 mA maximum current

sink, fault is open circuit.

19.9

Terrestrial Interface Types

19.9.1 Universal

The following interface types are available through the EIA-530 25-pin data I/O connector.

• EIA-232
• V.35
• EIA-422, MIL-188-114A

Optional mechanical interfaces are also available. See Chapter 5 for pinout information.

• 37-pin D (EIA-449)
• 34-pin Block (V.35)
• 50-pin D

• G.703 with DB9 and BNC (Closed Network with ASYNC)
• Eurocomm



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