Panasonic KX-TA1232 Service Manual page 47

RAM (IC48, IC49) into the PCM CODEC data, and presents to UHW 0 of the up highway.
Two of this circuit are installed on one card, and one of them has the OGM recording function as
well. In another words, it takes in the PCM CODEC data on DHW 6 of the down highway through
the AGC circuit and converts to the ADPCM codes.
The data transmission between this circuit and RAM (IC48, IC49) is done by CPU (IC1). The
transmitting rate is 1 Bite/250 S. This circuit is composed of the ADPCM IC with serial/parallel
converter and parallel/serial converter (IC53, IC54), CODEC IC (IC57,IC58, IC61) and the AGC
Circuit (only one circuit).
The coding rate of ADPCM is 32 Kbps.
OGM Memory Circuit
Composition:
SRAM 2 Mbit (IC48, IC49)
Battery (BAT), etc.
Circuit Operation:
This circuit is RAM (IC48,IC49) which is stored the ADPCM data of OGM by CPU (IC1). With 2 Mbit
capacity, two messages each for 32 seconds can be recorded. This circuit is backed up by
battery (BAT).
DTMF Repeat Circuit
Composition:
CODEC IC (IC520, IC21)
Filter IC (IC13, IC14)
DTMF Transceiver IC (IC9,IC10)
Circuit Operation:
This circuit is a circuit which receives the DTMF signal (IC9,10) through the highway (IC20-
IC13,IC21-IC14) once and resends (IC9,10) to the highway (IC20,IC21) to cover the level reduction
of the DTMF tone caused by the line loss during CO-CO call. Normally, output of this circuit is
open, and once it detects the DTMF signal(IC9,10)at CO-CO call, the output connects with UHW 6
of the up highway and then resends the DTMF signal (IC9,10).
Also this circuit is used as the DTMF receiver (IC9,10), and receives the secondary dial when the
DISA signal incoming.
Two of this circuit are installed on one card (TS16,TS18 of DHW6).
End of Call Detection Circuit
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