Modem Circuit Operation - Panasonic KX-FHD332C Service Manual

Signal
PRI-EOP
(Procedural Interrupt-
EOP)
PIP
(Procedural Interrupt
Positive)
b. Redundancy Compression Process Coding Mode
This unit uses one-dimensional MH format.

7.7.2. MODEM CIRCUIT OPERATION

The modem (IC505) has all the hardware satisfying the ITU-T standards mentioned previously.
When the ASIC IC501 (61) is brought to a low level, the modem (IC505) is chip-selected and the
resistors inside IC are selected by the select signals from ASIC (IC501) ADR0-ADR4(pin 83~87).
Commands are written through the data bus, and all processing is controlled by the ASIC
(IC501) according to ITU-T procedures. Here, the INT signal dispatched from IRQ (pin 60 of
IC505) to the ASIC (IC501) implements post processing.
This modem (IC505) has an automatic application equalizer. With training signal 1 or 2 at the
time of G3 reception, it can automatically establish the optimum equalizer. The modem (IC505)
clock is supplied by pin 55 of ASIC (IC501).
1. Facsimile Transmission/DTMF Line Send
The digital image data on the data bus is modulated in the modem
(IC505), and sent from pin 44 via amplifier IC501(2
Identification Signal Format
X1111100
X0110101
If there is an operator call from the sender, it
after RTC.
This is output when an operator call is received.
183
Function
1), Analog SW