Pub. 42004-178D
Model 263 Isolation Barrier Unit (IBU)
Page: 8 of 13
\\s_eng\gtcproddocs\standard ioms - current release\42004 instr. manuals\42004-178d.doc
03/06
Maintenance
This section includes two troubleshooting charts designed to quickly pinpoint the source of problems.
Troubleshooting
N
OTE
:
It may be advantageous to temporarily connect an I.S. telephone panel directly to the output
terminals of the Model 263 IBU when troubleshooting. Then, using the charts below, the cause of the
problem should be more easily determined.
Non-Equipment Related Problems
Problem Solution
The I.S. phone is inactive with
no lights on the IBU when the
phone is off-hook.
1.
Check the ac power to the Model 263 IBU.
2.
Check the ac fuse F4 at the Model 263 IBU.
3.
Ensure there is no wiring open at the I.S. phone.
1.
If the I.S. phone has a wiring short, the IBU lights will be lit in
the following pattern:
O
=
On
,
P
= Off
ISLOOP
O
LOCK
P
HOOK
P
TELCO
P
2.
If the TELCO line has an open, the IBU lights will be lit in the
following pattern: :
O
=
On
,
P
= Off
ISLOOP
O
LOCK
O
The I.S. phone has no dial tone.
HOOK
O
TELCO
P
The lights on the IBU flash
randomly.
The I.S. phone has an intermittent wiring short. The short may be
between the conductors or either/both conductor(s) to ground/shield.
