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5−
5
d. Provides monitoring and alarm information to the 54560 Alarm Interface
Card in the event of:
1. Loss of input signal (LOS)
2. Loss of frame (LOF)
3. Excess bipolar violations (BPVs)
e. Includes one-wire interface to 54550 for reporting personality (Model, List,
Issue, revisions, Larus serial number, customer inventory control
information, and other customer designated data), framing, light-emitting
diode (LED) status, and slot ID.
5.32 Circuit
Description
Refer to the 54511/54512 Input Card block diagram, Figure 5-2, in the
following discussion.
5.3210 E1/DS1
Conversion
E1 clock signals (2.048 MHz) are converted to DS1 signals (1.544 MHz) by
clock adapters (CLADs) on the input card and the 54541/54542
Synchronization Monitor Card.
5.3211 T1/E1
Receiver
The T1/E1 receiver recovers the data and clock from the T1/E1 input
reference. The recovered clock and data are fed to the Receive Framer (RCV
FRMR) from a +20 dB amplifier. The RCV FRMR tests for certain input error
conditions. The recovered clock is also passed to output buffers.
The T1/E1 receiver chip recovers the clock and data from the input signal.
The clock recovery oscillator in the receiver is synchronized to the amplified
and full-wave rectified input signal. The oscillator tracks the input bit rate
exactly, as long as excessively lengthy sequences of zeros (more than 15
consecutive zeros) do not occur.
The T1/E1 receiver outputs the data in dual rail format, one output that
represents positive voltage excursions and another for negative voltage
excursions of the input.
