Panasonic KX-TA1232, Service Manual

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same as Conference Circuit
Circuit Operation:
Tone Generator Circuit presents 4 kinds of the call progress tone and 2 channels of the DTMF
tone to DHW0 of the down highway. This circuit consists of the Gate Array (IC2) and ROM (IC19)
which are common to the conference circuit. ROM (IC19) are stored in the PCM data of the tone.
Gate Array makes ROM address, gets tone data from ROM and sets the data on the highway.
Clock Generator Circuit:
Composition:
same as Conference Circuit
Circuit Operation:
The clock Generator circuit is a circuit which generates PCM clock from X’tal (X1) and Gate Array
(IC2). The generated clocks are shown below.
C4MN: 4.096 MHz Highway clock
C2M: 2.048 MHz Highway clock
FH1N: 8 kHz Frame pulse
CHS0~4: 128, 64, 32, 16, 8 kHz Channel select signal
CP27~31: 8 kHz Synchronous signal for
CODEC
The sources of these clocks are the local OSC of 8.192 MHz Crystal (×1). Switching the clock
sources is controlled by CPU (IC1).
Clock circuit
Composition:
Real Time Clock IC (IC26)
Circuit Operation:
Clock Circuit is a circuit which gives the clock function for this system, and consists of the clock
IC (IC26) backed up by the batteries. This circuit presents one second interruption to CPU (IC1).
Hold tone circuit
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