Philips SBX12, Operating Instructions Manual

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24
SECTION VI
GENERAL FACILITIES AND TEST PROCEDURES
Incoming Calls
An incoming call will ring the operators telephone and if not answered within time period, will
also activate system bells (AC bells) as required by the subscriber.
Calls can be answered direct by the operator, or any extension may answer by dialling 2 or 20
(Universal Pick-up).
Also incoming calls can be answered direct by extensions selected by C.O.S. To transfer a call,
the extension flashes the switch-hooks to receive internal tone.
Mains Fail
In the event of a power failure, the trunks are switched to predetermined extensions. If the
system trunks are earth start, the mains fail extension will require a recall button.
Mains fail extensions:
L1 – 89 NOTE: When the SBX system is installed
with decadic trunks to the exchange
L2 – 88 and the subscriber requires all
extensions to be push button
L3 – 87 telephones, a Plan 1 rotary dial
telephone is provided at one Mains
L4 – 86 Fail Station free of installation
and rental charges.
L5 – 85
SIGNALLING
The SBX will recognise DTMF or Decadic signals from any extension.
The SBX is set at installation for either DTMF and/or Decadic exchange lines by setting switches
on the trunk board. Dialling signals are regenerated or converted as required.
Exchange line signalling is achieved using two wire loop start or on MK3 trunk board only, B-line
earth start.
Outdialling commences on receipt of exchange Dial Tone and audio connection occurs at the end of
outdialling. The SBX assumes that outdialling has finished when the outdialling buffer is empty
and there has not been an input to the buffer for the last 4 seconds. However, for line access
digit 1 three “tables” are stored, STC, Non-STD and Step 10 and entering matching numbers gives an
immediate number complete condition.
For PABX parenting, detection of further Dial Tone after the completion of outdialling prevents
the number complete condition occurring and returns Dial Tone to the calling extensions.