Panasonic KX-1T7533G Service Manual page 16

KX-T7533G/KX-T7533G-B
4. DATA COMMUNICATION CIRCUIT
1) Function
The data communication circuit serves the following functions:
Information exchanger between the DSHS and DSHS proprietary telephone, key input information as well as data for
the LED control, LCD control, etc. This information is continuously exchanged at all times.
2) Circuit Operation
When the DSHS proprietary telephone receives an IRQ signal from the DSHS and after sending the key input
information to the DSHS and receiving data for the LED control, etc., the DSHS proprietary telephone will return to the
DSHS an acknowledge signal.
3) Reception
The data from the DSHS is received via the H and L lines along the path shown below.
H, L Line + T1 > 1C11 Pin 5, 10 > IC1 Pin 38, 39 > IC1 Pin 21 > IC2 Pin 22
4) Transmission
The data to the DSHS proprietary telephone is transmitted along the following path.
IC2 Pin 23 > IC1 Pin 20 > IC1 Pin 40, 41 — Q1, Q2 5 T1 5H, L Line
Circuit Diagram
IC2
COMMUNICATION LS!
TO HANDSET
SP-PHONE
XDP PORT
RXA
Reception
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