LLM Line Link Test (#75)
Summary:
Step 1.
Step 2.
Step 3.
Note:
Step 4.
Step 5.
Step 6.
This procedure is used to check out all the LLM functions for each line. These include: off-
hook sense, audio to each link, DC, and ringing. This test will interfere with anyone using the
system. Hang up the test phone to halt the test at any time.
Dial #75 from the display phone, then enter the physical number of the first line to be tested.
Note that the following prompt, CONNECTION TIME?
,
appears on the test phone display.
Enter a value (in 6Oths of a second increments) and press # (e.g.: 30#
for
l/2 second).
Verily a single ring occurs at the phone associated with the specified physical number.
Step 4 is complex. Before beginning it, prepare to note the time (in seconds) at which the
target phone is taken off-hook and be ready to send a DTMF tone from the target phone to
the test phone.
Take the target phone off-hook and verify a clear communication path exists between it and
the test phone for a period of time equal to 16 times the time period specified in Step 2. (i.e.:
if Step 2 value is 120, this period is 32 seconds).
Note: During this time period, the system is making and breaking the connection between
the two phones via each link in the system, starting at 0 and proceeding sequentially
to 15. The length of each connection is determined by the value entered in Step 2.
The tone should be clearly audible and subdued clicks may be heard as each link is
made and broken. If the value in Step 2 is high enough the click will be slow enough
to count.
Verily a dead line exists for a few seconds after the time period identified in Step 4 and that
this is followed by another sequence as specified in Step 4.
If a link is faulty, the tone will be interrupted during the connection. To determine
which link is faulty, count the clicks, starting at 0. Use the Bus I/O diagnostic to
verify
your finding or to check the links individually.
If an on-hook phone is available on the line at the next physical number, hang up the first
phone and verify the next one rings; then, take it off hook and verify the results obtained in
Steps 4 and 5. This process can be quickly advanced down the line to test a complete LLM
module.
