Panasonic KX-TA1232 Service Manual page 41

When power fails or 117 pin of IC211 becomes low, collector of Q221 is high, RLY200 turns OFF
and make the path.
DTMF Receiver Circuit
Composition:
DTMF Receiver IC (IC215, IC216)
8 R1 Analog Switches (IC217, IC218)
Circuit Operation:
DTMF Receiver Circuit is a circuit for receiving the DTMF dials presented by STL and APT. This
circuit is composed of the 8 1 Analog Switches (IC217, 218) and the DTMF Receiver IC (IC215,
216). This circuit is incorporated two lines on card, each line is connected through the eight
extensions and the analog switches (IC217, 218) to the DTMF receiver IC (IC215, 216).The
received data of DTMF receiver are read through the data bus by the main CPU (IC1).
APITS Data Communication Circuit
Composition:
Gate Array (IC211)
Circuit Operation:
APT Data Communication Circuit is a circuit which performs the serial/parallel conversion of the
control data between APT comm. paths and the main CPU (IC1). This circuit covers 8lines
corresponding to each extension, and 8 line are integrated into on Gate Array (IC211).
HDLC Controller
Composition:
HDLC Controller IC (IC213)
Circuit Operation:
HDLC Controller is a circuit which functions the data format conversion of the D channel
between the DPITS comm. line installed with a Gate Array (IC211) and the CPU data bus by
following the HDLC protocol. The serial/parallel conversion is done at the same time. Though this
circuit communicates with 8 channel of the DPITS comm. circuit, since it can communicate only
with one channel at a time, as before mentioned it, switches the communicating extension every
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