Troubleshooting guide

MX2820 System Manual
7-38 61186003L1-1D
b. Wire wrap one strand to the MIN Normally Closed (NC) post, and route wire downward.
c. Wire wrap one strand to the MIN Normally Open (NO) post, and route wire downward.
5. Route the wires to the Alarm Relay concentrator or to the external office alarm equipment,
and connect the wires according to local instructions.
Wire Wrap CLKB and CLKA Posts
1. If the STS-1 application is being deployed that requires external timing, measure and cut
six pieces of wire long enough to reach from the
CLKB and CLKA wire wrap posts to the
external clock source.
NOTE
Only CLKA should be wired if only one external clock source is uti-
lized.
2. Use the wire strippers to strip 1 inch to 2 inches from both ends of each wire.
3. Use the wire-wrap tool to wrap the strands on the MX2820 backplane (see Figure 7-6) as
follows:
a. Wire wrap one strand to the post labeled S for the CLKB terminal, and route wire
downward.
b. Wire wrap one strand to the post labeled R for the CLKB terminal, and route wire
downward.
c. Wire wrap one strand to the post labeled T for the CLKB terminal, and route wire
downward.
d. Wire wrap one strand to the post labeled S for the CLKA terminal, and route wire
downward.
e. Wire wrap one strand to the post labeled R for the CLKA terminal, and route wire
downward.
f. Wire wrap one strand to the post labeled T for the CLKA terminal, and route wire
downward.
4. Route the wires to the external clock source, and connect the wires according to local
instructions. Figure 7-7 provides an example for wiring the clock terminals on the
MX2820 backplane to an external clock source.