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Configuration
Distance to DSX (Ft)
(See Note 1)
(applies only to
22–GA. PIC
[ABAM] Cable)
Notes:
Three fault outputs are provided on dry contact FORM C relays:
•
•
•
The faults are available on the fault connector on the modem rear panel. Generation of
these fault conditions is described in Chapter 4.
Fault indicators are also provided on TTL open collector drivers on the DS-1 connector.
•
•
In order to facilitate testing of the modem when a DS-1 signal is not available, the output
of the clock recovery circuitry is replaced by a 1.544 MHz clock whenever loss of the SD
signal is detected. This allows the modem to generate its test signals at the proper data
rate.
A TXC-LOSS fault will occur in the Common Equipment fault menu whenever the
incoming data is missing.
3–22
Table 3-3. Equalizer Control
0 to 133
133 to 267
167 to 400
400 to 533
533 to 655
Test Clear
1. Other bit combinations represent test modes and are not used for normal
operation.
2. Use maximum loss figures for other cable types.
Common Equipment
Modulator
Demodulator
The TTL MOD fault indicates a Modulator fault or Common Equipment fault.
The TTL DEMOD fault indicates a Demodulator or Common Equipment fault.
Maximum Cable
4
Loss
(dB at 772 kHz)
EC1
0.6
C
1.2
C
1.8
C
2.4
C
3.0
O
---
O
SDM-650B Satellite Modem
SW1
(See Note 2)
3
2
EC2
EC3
C
C
C
O
O
C
O
O
C
C
C
O
Rev. 5
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