Specifications

Reference Guide
6-11
Interface Card Interface Card User Screens and Settings
connection panel (see Figure 6-4). This panel allows for up to two external timing sources to
be connected to the system. Refer to
EXT FORMAT
below for more information on external
source clocking.
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,
user card, or external source, or it can be the system’s internal crystal oscillator. Although a
secondary clock source is not required for system operation, you should always provide one
for the system.
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
.