Panasonic KX-TA1232 Service Manual page 28

Function
Sending OGM
DTMF signal detection
Call between CO lines
DTMF repeat
End of call detection
OGM record
FIFO communication
(5) CALLER ID CARD (KX-TA123293)
CALLER ID CARD is an optical card corresponding to "caller ID service" available in the north
American market. This board is added on the CO board and detects the 300 bps modem signals
transmitted during recesses between the bell signals form the station, and convents them into
the parallel data.
One card is corresponded to the 4 lines. Two cards can be installed on the BASIC CO BOARD (8
lines) and one board can be installed on the EXPANSION EXT BOARD (4 lines).
8. EXPLANATION OF CIRCUIT OPERATION
8.1. BASIC
(1) POWER SUPPLY UNIT
POWER SUPPLY UNIT consists of the following.
Line Filter Section
Rectifier and Smoothing Section
Switching Section
Control Section
+15 V Circuit
-15 V Circuit
+5.3 V Circuit
Bell Amp Circuit
Line Filter Section
Common mode noise is removed by C401, C402 and C405 to C406, and normal mode noise by
L400 and L401. Lightening surges are absorbed by CR400, CR401 and SA400.
Sending OGM (Out Going Message) stored in RAM to the CO line. 2 types
OGM for 32 sec. each are stored.
After sending OGM to CO line, detecting the in-coming signal of DTMF.
Two call paths for call between CO lines.
When calling between the CO lines, resending the received DTMF to
maintain the certain level of the DTMF signals.
When calling between the CO lines, detecting the no tone, the cyclic tone
and the continuous tone.
2 channels/1 path, total 4 channels
Recording the OGM from the specific extension into RAM. Controlling the
level by AGC circuit.
Only one channel is available as the recording channel.
Communicating between CPU on this card and main CPU through FIFO
memory.
28
Description