A DDP2 loop is disabled when it enters a local-alarm condition. If the local alarm is cleared,
the loop is enabled automatically. When the loop is enabled, clock tracking is restored in the
following conditions:
• If the loop is assigned as the primary reference clock but the clock controller is tracking
on the secondary reference or in free-run mode, it is restored to tracking on primary.
• If the loop is assigned as the secondary reference clock but the clock controller is in free-
run mode, it is restored to tracking on secondary.
• If the clock check indicates the switch is in free-run mode:
- Tracking is restored to the primary reference clock if defined.
- If the primary reference is disabled or in local alarm, tracking is restored to the
secondary reference clock if defined.
Note:
If the system is put into free-run mode by the craftsperson, it resumes tracking on a
reference clock unless the clock-switching option is disabled (LD 60, command MREF),
or the reference clock is "undefined" in the database.
Automatic clock switching
If the EREF command is selected in LD 60, tracking on the primary or secondary reference
clock is automatically switched in the following manner:
• If software is unable to track on the assigned primary reference clock, it switches to the
secondary reference clock and sends appropriate DTC maintenance messages.
• If software is unable to track on the assigned secondary reference clock, it switches to
free run.
Clock configurations
Clock Controllers can be used in a single or a dual CPU system.
A single CPU system has one Clock Controller card. This card can receive reference clocks
from two sources referred to as the primary and secondary sources. These two sources can
originate from a PRI2, DTI2, etc. PRI2 cards such as the NT8D72BA are capable of supplying
two references of the same clock source. These are known as Ref1 (available at J1) and Ref2
(available at J2) on the NT8D72BA.
The NT5D97 card is capable of supplying two references from each clock source, for example,
four references in total. NT5D97 can supply Clk0 and Clk1 from Unit 0 and Clk0 and Clk1 from
Unit 1. Either Unit 0 or Unit 1 can originate primary source, as shown in
Figure 87: Clock Controller - Option 4
on
page 288.
Architecture
Circuit Card Reference
July 2011 283
Summary of Contents for 1000 Series
Page 1: ...Circuit Card Reference Nortel Communication Server 1000 7 0 NN43001 311 04 04 July 2011 ...
Page 20: ...20 Circuit Card Reference July 2011 ...
Page 30: ...Introduction 30 Circuit Card Reference July 2011 Comments infodev avaya com ...
Page 116: ...Option settings 116 Circuit Card Reference July 2011 Comments infodev avaya com ...
Page 143: ...Figure 25 CP PIV card front Physical description Circuit Card Reference July 2011 143 ...
Page 148: ...NT4N39AA CP Pentium IV Card 148 Circuit Card Reference July 2011 Comments infodev avaya com ...
Page 287: ...Figure 86 Clock Controller Option 3 Operation Circuit Card Reference July 2011 287 ...
Page 302: ...NT5K21 XMFC MFE card 302 Circuit Card Reference July 2011 Comments infodev avaya com ...
Page 346: ...NT6D80 MSDL card 346 Circuit Card Reference July 2011 Comments infodev avaya com ...
Page 353: ...Figure 96 NTDK16 DLC Functional description Circuit Card Reference July 2011 353 ...
Page 461: ...Figure 147 Paging trunk operation Applications Circuit Card Reference July 2011 461 ...
Page 462: ...NT8D15 E and M Trunk card 462 Circuit Card Reference July 2011 Comments infodev avaya com ...
Page 500: ...NTAK09 1 5 Mb DTI PRI card 500 Circuit Card Reference July 2011 Comments infodev avaya com ...
Page 512: ...NTAK10 2 0 Mb DTI card 512 Circuit Card Reference July 2011 Comments infodev avaya com ...
Page 534: ...NTAK79 2 0 Mb PRI card 534 Circuit Card Reference July 2011 Comments infodev avaya com ...
Page 550: ...NTBK22 MISP card 550 Circuit Card Reference July 2011 Comments infodev avaya com ...
Page 560: ...NTBK50 2 0 Mb PRI card 560 Circuit Card Reference July 2011 Comments infodev avaya com ...
Page 595: ...Figure 165 MGC block diagram Introduction Circuit Card Reference July 2011 595 ...
Page 662: ...NTRB21 DTI PRI DCH TMDI card 662 Circuit Card Reference July 2011 Comments infodev avaya com ...
Page 668: ...NTVQ01xx Media Card 668 Circuit Card Reference July 2011 Comments infodev avaya com ...
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