Panasonic KX-TES824LA, Service Manual

Page: 220 / 289

26.5.5. DATA Communication Circuit
26.5.5.1. Composition
This circuit is composed of the ASIC and the data communication interface circuits for the ICM circuit.
26.5.5.2. Circuit Operation
1) Data Communication of ASIC
The APT I/f module is built into the CPU. It is for the APT communication of one block (8ch) and has the module of three blocks
(24ch) at maximum.
selection signal of 3 bits to select 1ch out of 8chs is common to each block.
The APT I/f module switches the communication point every 4ms in the ports 1-8/9-16/17-24 of the extension as follows:
#101
→ #102 → #103 → #104..... → #108 → #101.....,
#109 → #110 → #111 → #112..... → #116 → #109.....,
#117 → #118 → #119 → #120..... → #124 → #117.....,
In the case where the extension is not connected with the APT, it is recognized as an SLT connection and a dummy
communication is performed.
Interface block diagram of ASIC and ICM
2) Data Communication of ASIC and PITS
When ASIC send the request signal to the proprietary telephone and after receiving the key input information (19 pulses) from
the proprietary telephone and sending data (47 pulses) for LED control. ASIC will receive acknowledge signal from the
proprietary telephone.
a) Reception
The data from the proprietary telephone is received via H and L lines along the path shown below.
H.L line
→
C208
→
IC200
→
T201
→
R235
→
Q210
→
ASIC
b) Transmission
The data to the proprietary telephone is transmitted along the following Path.
ASIC
→
Q209
→
Q215
→
T201
→
IC200
→
C208
→
H.L line
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KX-TES824LA / KX-TEM824LA /