Philips SBX12, Руководство по эксплуатации

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11
Link Card
One of three cards associated with the 12E.
The link circuit provides the following functions:
1. Powering of an extension.
2. Pick off for extension generated DTMF or loop disconnect signals.
3.
Tone injection to extensions.
4. Tone cadencing to extensions.
Dual Tone Multiple Frequency Card
The DTMF is a single card but on it are two DTMF receivers and a transmitter.
The operation of DTMF receiver.
1. Decodes signals from the links.
2. Converts the information and sends the digital information to the CPU.
3. Either free DTMF receiver can be connected to any link in the 12E.
DTMF Transmitter Operation.
1. It generates DTMF signals for sending to an exchange.
2. Provides DTMF tone to trunks on a time multiplex basis, i.e. tone bursts are provided to one
trunk during the interdigit pause on the other. This multiplexing is controlled by the CPU.
SYSTEM BELL
The system bell is powered by the ringing current via relay contacts, so only an A.C. device is to be
used. The feed provides approximately 40mA maximum.
Bell Type:
Sonalert electronic bell S.L. No. K41 with a 2uF capacitor wired in series. The Sonalert bell
requires 10 – 16mA current.
PROTECTION
The system is protected using fusible links and voltage dependant resistors on all extension and
trunk lines.