Panasonic KX-T7453, Service Manual, Page: 18 / 57

times.
2) Circuit Operation
When the DSHS propritary telephone receives an IRQ signal from the DSHS and after sending the key
input information to the DSHS and receivung 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 IC11 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 T1 H, L Line
5) IC1 (GATE ARRAY) DPITS Interface
DPITS Layer 1 interface. DR [1:0] is receiving input and DX [1:0] is transmitting output.
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