GAI-Tronics 1090, Инструкция по установке и эксплуатации

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6 VR & Help Point
3.3. Ending the Call
There is no direct way for a user to end a call from the unit. The unit will close
down and release the line on receipt of the following signals, usually when the
remote party clears:
•
Line polarity reversal
•
A line break (sometimes referred to as a “k break”).
•
Receipt of exchange call progress tones (see section 10 for specification)
3.4. Call timer
The phone has a programmable call timer that can limit the maximum call
duration.
When ON, the timer forces the phone back off line after the preset time. This
prevents the line remaining tied if the neither party ends the call. The timer is
factory-set to 7mins by default, but can be set to any value (up to 2¾hrs) or
disabled. See section 7.2.1.
3.5. Semi Duplex Operation
The Help Point is semi duplex, with automated switching between transmit
and receive depending on which signal is the stronger. It therefore requires
an adequate signal level to be able to switch into receive mode. This level
may vary according to ambient noise levels at the Help Point, but we would
recommend ensuring that the incoming signal level received at the Help point
is at least -35dBm.
This level may have to increase if the ambient noise level at the Help point is
high, and in any event correct operation cannot be guaranteed in ambient
noise levels exceeding 80dBA.
Semi duplex operation can also be affected if the impedance of the telephone
line differs significantly from the pan-European standard – see section 10.
4. SMART features
This family of products has a wide range of intelligent features including:
•
Monitoring of faults and health status
•
Remote programming of auto-dial numbers and configuration parameters
•
Alternate day / night autodial numbers
•
Call logs for calls made to and from the telephones
1
1
Called Party Answered signalling (CPA), ie a reversal of line polarity when an
outgoing call is answered, is required to ensure accurate recognition of call
connection and answer delay times. CPA is a telephone line service and may not
be available from all telecom service providers.