CXR Larus 80-100-400
Issue 1, July 2006
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NOTE:
Model 54522 and 54523 track and hold cards are provisioned at the factory with either
AA or AB input architecture and Models 54591 and 54593 with AB architecture only.
Refer to Appendix A. Assuming that there are acceptable DS1/E1 signals at Inputs A
and B:
a.
For the AA input architecture, the normal reference for both track and
hold cards is DS1/E1 Input A.
b.
For the AB input architecture, the normal reference for the A track and
hold card is DS1/E1 Input A and for the B track and hold card, DS1/E1 Input B.
In the tracking state, the Input A LEDs are illuminated on both track and hold cards.
References can only be changed by commands from a terminal as described in the
Volume 3 (TL1/ITL1) or Volume 4 (Menu) User Manual.
4.22
Selection of Clock Source for Output Driver Cards
4.2210 Selection of the clock source is made from the 54550 Information Management
Card. Normally, the clock source is selected automatically on the basis of which
clock is available first and which is not in alarm state.
4.2211 The manual clock select mode is activated by pressing the RESET
originator/recipient (O/R) button until the OVERRIDE LEDs on the 54550 and
on all the output driver cards except the Model 54576 turn on.
4.2212 Pressing the A/B CLOCK SELECT button once will cause the output cards to
select the next clock in the sequence CLOCK A, CLOCK B, INPUT A, INPUT B.
The selection will be shown on the output card LEDs. Pressing it again will
advance the sequence by one more and so on.
NOTE:
Do not leave an operational system with INPUT A or INPUT B selected unless both A
and B track and hold cards have completely failed. In this state, the system has no
holdover capability and does not appreciably attenuate jitter and wander on the input
references.
4.2213 To return to the automatic clock select state, press the RESET O/R button until
the OVERRIDE LEDs turn off. If no better source is available, the system will
stay where it is. If a better source is available, the system will automatically
select that source. Refer to the 54500 Clock Auto-selection State Diagram,
Figure 4-1.
Содержание 54500-16
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