Maincomponents; Facilities; Circuitdescription - Mitel SX-200 Practices

Circuit Card Descriptions
between the console, processor and the bay processor via the console module
processor. The remaining two channels are reserved for future use,
The Console Interface Module feeds -48 Vdc to the console. Current is limited to about
120 mA.
The Console Interface Module has a power rating of 5.
DTiF Receiver/Relay Module
,Brief Description
7.6 The DTMF Receiver/Relay Module facilitates the reception and decoding of DTMF
dialing.
Main Components
Major components of the DTMF Receiver/Relay Module are:
9 Mite1 filter/codec (four)
9 Mite1 8870 DTMF receiver (four)
l
Parallel bus interface
l
Guard time circuit (four)
l
General Purpose relays (two).
Facilities
Facilities provided by the DTMF Receiver/Relay Module include:
l
Early line split
9 Guard time circuit
9 Presents digits on parallel bus with Data Valid signal
l
Two general purpose relays.
s
Circuit Description
There are four receivers on the DTMF module. Each receiver takes its input from the
incoming serial PCM audio stream and repeats this data to the outgoing serial PCM
stream approximately 125 msec later. A filter/codec converts the data to analog audio
which is monitored by a DTMF Receiver chip. When DTMF tones are detected, the
loopback of the data to the PCM output stream is disabled. (Early Line Split). The DTMF
Receiver/Relay Module has a power rating of 2. See Table 7-l.
Two relays are on the module; each is software controlled to provide a contact closure
across one tip-ring pair.
125 7-4
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9109-096-125-NA Issue1