Troubleshooting
Notes:
1.
An on-hook LLM phone will ring each time a connect signal is sent to it. The ring
burst is hardware controlled by a logic hybrid and plug-in LLM line hybrid.
2.
If you connect two LLM lines to the same link, they can communicate until one is
dis-
connected
or the system is reset.
3.
Sending a speaker connect signal will cause an audible click on the SC25 as the relay
energizes. A V will appear in the display if a speaker is connected to the designated
circuit.
Caution:
If you disconnect or change links on either your own (the display phone’s) physical number
or that of the line used for the DTMF register, use of the display phone for communication
and
testing
will be terminated and the system will have to be RESET.
Test Tone
A 941 Hz. test tone (5 seconds on and 5 seconds
off)
can be obtained for performing audio
measurements or listening tests. The tone is available to the test phone or any phone in the
link with it. Little display interaction is required, so any phone can be used which has its
B:78
attributes set to on. Tone levels are affected by the phone’s impedance, the test phone line
hybrid, the number of phones in the test link, and component tolerance in the MI0 generator
circuits. Typically, tone levels are as follows:
.25
vrms,
-10 dbm at the receiver connection to an LLM (0 or 1)
.10
vrms,
-17 dbm across a phone line.
Note:
The telephone keys
operate as a two by
three matrix: Each
vertical pair (e.g.: 1
and 4, 8 and 0, etc.,)
addresses a common
function (i.e.: LLM,
Speaker Relay, etc.).
The uppermost key
makes a connection
or increments a
numerical value and
the lower key of a
pair ends a connec-
tion or decrements a
numerical value.
Line
Link
No.
Decrement
1989
Rauland-Borg
Corporation (Orig.
10/88;
Rev.
l/89)
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