Page 490 of 544
NTAK79 2.0 Mb PRI card
553-3011-100
Standard 14.00
January 2002
If the software command “track to secondary” is given, the clock controller
tracks to the secondary reference and continuously monitors the quality of
both primary and secondary references. If the secondary becomes out of
specification, the clock controller automatically tracks to primary provided
that it is within specifications. On failure (both out of spec.), the clock
controller enters the HOLDOVER mode and continuously monitors both
references. An automatic switchover is initiated to the reference that recovers
first. If the primary recovers first, then the clock controller tracks to the
primary, but switches over to the secondary whenever the secondary
recovers. If the secondary recovers first, then the clock controller tracks to the
secondary.
A time-out mechanism prevents chatter due to repeated automatic switching
between primary and secondary reference sources.
Holdover and free-run
In the temporary absence of a synchronization reference signal, or when
sudden changes occur on the incoming reference due to error bursts, the clock
controller provides a stable holdover. The free-run mode is initiated when the
clock controller has no record of the quality of the incoming reference clock.
If the software command “free run” is given, the clock controller enters the
free-run mode and remains there until a new command is received. Note that
the free-run mode of operation is automatically initiated after the clock
controller is enabled.
Reference clock selection via software
The NTAK79 has the necessary hardware for routing its reference to the
appropriate line on the backplane
Software is responsible for the distribution of the secondary references and
ensures that no contention is present on the REFCLK1 backplane line.
Software designates the NTAK79 as a primary reference source to the clock
controller. The secondary reference is obtained from another NTAK79 card,
which is designated by a craft person. No other clocks originating from other
NTAK79 circuit cards are used.
Содержание Meridian 1 Option 11C Mini
Страница 2: ......
Страница 8: ...Page 8 of 544 Contents 553 3011 100 Standard 14 00 January 2002 ...
Страница 10: ...Page 10 of 544 About this guide 553 3011 100 Standard 14 00 January 2002 ...
Страница 86: ...Page 86 of 544 Memory Storage and CPU capacity 553 3011 100 Standard 14 00 January 2002 ...
Страница 176: ...Page 176 of 544 Transmission parameters 553 3011 100 Standard 14 00 January 2002 ...
Страница 196: ...Page 196 of 544 Spares planning 553 3011 100 Standard 14 00 January 2002 ...
Страница 226: ...Page 226 of 544 System Controller cards 553 3011 100 Standard 14 00 January 2002 ...
Страница 260: ...Page 260 of 544 The TDS DTR card 553 3011 100 Standard 14 00 January 2002 ...
Страница 282: ...Page 282 of 544 M2317 Telephone 553 3011 100 Standard 14 00 January 2002 ...
Страница 308: ...Page 308 of 544 Meridian Modular Telephones 553 3011 100 Standard 14 00 January 2002 ...
Страница 312: ...Page 312 of 544 M3900 telephone series 553 3011 100 Standard 14 00 January 2002 Figure 40 M3901 Figure 41 M3902 ...
Страница 364: ...Page 364 of 544 M2250 Attendant Console 553 3011 100 Standard 14 00 January 2002 ...
Страница 368: ...Page 368 of 544 NT8D02 and NTDK16 Digital Line Cards 553 3011 100 Standard 14 00 January 2002 Figure 55 NTDK16 DLC ...
Страница 388: ...Page 388 of 544 NT8D14 Universal Trunk Card 553 3011 100 Standard 14 00 January 2002 ...
Страница 408: ...Page 408 of 544 NT5K21 XMFC MFE card 553 3011 100 Standard 14 00 January 2002 ...
Страница 414: ...Page 414 of 544 NTAG26 XMFR card 553 3011 100 Standard 14 00 January 2002 ...
Страница 422: ...Page 422 of 544 NT6D71 UILC line card 553 3011 100 Standard 14 00 January 2002 ...
Страница 438: ...Page 438 of 544 NT1R20 Off Premise Station OPS analog line card 553 3011 100 Standard 14 00 January 2002 ...
Страница 492: ...Page 492 of 544 NTAK79 2 0 Mb PRI card 553 3011 100 Standard 14 00 January 2002 ...
Страница 512: ...Page 512 of 544 NTAK20 clock controller 553 3011 100 Standard 14 00 January 2002 ...
Страница 518: ...Page 518 of 544 NTAK93 D channel handler interface 553 3011 100 Standard 14 00 January 2002 ...
Страница 544: ...Page 544 of 544 Index 553 3011 100 Standard 14 00 January 2002 ...
Страница 545: ......