Troubleshooting
Cradle Switch Test
Step
1.
Dial a trunk and get outside dial tone.
Step 2. Attempt to send a hook-flash
using
the cradle switch instead of the TAP button. The TAP
circuit in the phone should extend the on-hook time sufficiently to allow disconnect.
Step 3. Verify TCIV dial tone.
Step 4. Dial another TCIV extension and verify that only a single ring occurs. If a double ring occurs,
the TAP phone did not force a disconnect, allowing the possibility that a rapid hang-up and
answer sequence will initiate a transfer.
Step 5. If a double
ring
occurred in Step 4, one of the following actions is indicated.
Phone disconnect is less than 1.5 seconds. Replace phone.
TClV hookflash time is set too long (refer to Programming Section and ensure
that the value in location Code 64014 is 65).
Step 6. Repeat Steps 1 through 4 five times in a row to assure repeatability.
Ground Resistance Measurement
A good ground is important for reliable and safe operation of a TCIV system. The ground
should also bc common to any associated systems such as Key systems or PBXs. The resistance
of the ground connection can be measured as follows by referring to
Drawing
KC1461.
Step 1. Connect one end of a
100 ohm,
2 watt resistor to one of the + 12 Vdc (M) terminals on the
MIO.
Step 2. Connect an 18-AWG wire between the other end of the resistor and a good ground, such as a
cold water pipe or conduit main. Do not use the same ground connection used by the rack.
Step 3.
With TCIV power on, measure the d.c. voltage between the resistor and any MI0 Z terminal,
or switch panel Z, or the cabinet itself. The voltage should be
less than 120 mvdc
which
corresponds to a resistance of 1
ohm.
Loss Measurement
If excessive loss is suspected in a TCIV line, measure it with the following procedure. If
necessary, refer to the Programming Section and temporarily reprogram the lines to be tested
as administrative phone lines and/or equip them with line hybrids.
Step 1. Connect commercial quality phones to two LLM lines and place them in communication with
one another.
Step
2.
Hold down the bottom row of tone buttons on one phone, the
Originator,
to send a pure
941 Hz tone to the other phone, the Listener.
Step 3. Using a digital meter of sufficient bandwidth for audio frequencies, measure the millivolt level
on the two respective T
and R terminals
and verify that the Originator to Listener difference
is less than 9db. Typical reading arc shown below.
Originator 300 mvrms 0 db (ref)
Listener 130 mvrms -7 db
1989
Corporation (Orig. 10/88; Rev. t/89) Page
21 of 30
