Zhone IMACS 8000 User Manual page 281

Interface Card
Select user for a primary clock from a BRI card in the system. If you select user, also specify
the chassis slot location of the desired card (U1 to U8), followed by the card port from which
the clock will be provided (u1-1 through u8-8) as required. If you select a chassis slot that
contains any other type of user card, the message CARD CANNOT BE SELECTED appears.
If your system has an INF-E card, AND if external synchronization clocks are connected to
its SYNC jack, select either ext1 or ext2. The options ext1 and ext2 are used when the primary
clock is derived from an external timing source.
Refer to EXT FORMAT below for more information on external source clocking.
Select oc3 if you want the system to time off of the oc3 card. Once selected, then selection
must be made as to slot P1, P2 or P3 oc3 card. Once the card has been selected, then set the
oc3 clock to be either looptimed or internal. The best configuration using an OC3 is to have
the Central Office side of the configuration on a EXT clock source, and the remove system
timed off the OC3 in looptimed mode.
Once a clock mode for the IMACS has been set, then the system will attempt to sync onto that
clock source and the source will go active. In the case where a clock has been locked onto
drops for any reason, the IMACS will enter into holdover mode if all clocking options have
been lost.
EXT RATE
Set this option for the primary clock to t1 for a 1.544 Mbps WAN clock, or to e1 for a 2.048
Mbps WAN clock. If all WAN links in a system are either T1 or E1, this option should
automatically default to the correct rate.
EXT FORMAT
If EXT RATE is t1, set this option to esf or d4, as required by the T1 link. This option does
not appear if the Line Rate is e1.
EXT FRAME
If EXT RATE is e1, set this option to crc or d-frm, as required by the E1 link. This option
does not appear if the Line Rate is t1.
SECONDARY CLOCK
If the Primary Clock signal fails, the system automatically switches to an operator-defined
Secondary Clock source. In the event of a failure to the Primary Clock Source, once it is fixed
it will automatically restart. The secondary clock source may be a different WAN link, server,
System Cards
Interface Card User Screens and Settings
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