KX-NCP1171XJ (serv.man2) - Panasonic PBX Service Manual (repair manual). Page 8

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• DPT data communications

Bch/Dch/Cch data is transmitted from the DTL/DTH terminal of ASIC, and the AMI-converted pulse signal is output to DPT
(between D1 and D2) by way of the driver U5 and the pulse transformer T1. The Bch/Dch/Cch data transmitted from APT is input
to the DR terminal of ASIC by way of the pulse transformer T1 and R13. ASIC compares VREF+ and VREF- with the input wave-
form, and receives a valid pulse.

• Bch communications

Communicated by the PCM data (64kbps Å~ 2) connected from the local highway by ASIC.
Used mainly for the audio signal of DPT.

• Dch communications

Communicated by the data (16kbps) protocol-converted by the HDLC controller in ASIC.
Used mainly for the control signal of DPT.

• Cch communications

Communicated by the data (8kbps) converted by the serial/parallel-converting circuit in ASIC.
Used mainly for recognizing the terminal model.