DOWNLOAD Panasonic KX-FT932RU-B / KX-FT932CA-B / KX-FT932UA-B / KX-FT934RU-B / KX-FT934CA-B / KX-FT934UA-B Service Manual ↓ Size: 4.44 MB | Pages: 127 in PDF or view online for FREE

37

It is composed of bell detection circuit, pulse dial circuit, line amplifier, sidetone circuits.

1. Circuit Operation 

The signal waveform for each point is indicated below. The signal (low level section) input to pin 23 of ASIC IC1 on the digital
board.
TEL LINE 

→ PC1 (1, 2 → 4) → CN1 (11) → {CN2 (11) →  IC1 (23)}

Note:{      } : inside the digital board

Normally (ON-HOOK condition), LINE RELAY (RLY1) is OFF. While OFF-HOOK, RLY1 turns ON. This LINE RELAY is con-
trolled by pin 130 of IC1 through the Q7.
ON-HOOK:
IC1 (130) Low Level 

→ Q7 OFF → RLY1 OFF

OFF-HOOK:
IC1 (130) High Level 

→ Q7 ON → RLY1 ON

Make state:
IC1 (130) High Level 

→ Q7 ON → RLY1 ON 

Break state:
IC1 (130) Low Level 

→ Q7 OFF → RLY1 OFF 

38

1. Circuit Operation

The reception signal received as output from line transformer T1 is given as input to R81, C17, R13 and IC2(2).
Then it is input to the reception system at an amplifier gain of 2.5 dB from pin (2).
The transmission signal is input from CN1 pin (5), and output to the TEL line through C11, R16, IC2(6,7) and T1. Without a
side tone circuit, the transmission signal would return to the reception amplifier via C28, R27 and R26. Here, the signal output
from CN1 pin (5) passes through C28, R23, R22, R82, C21 and R18, and enters the amplifier IC2 pin (3). This is used to can-
cel the return portion of the transmission signal. This is the side tone circuit.

39

1. Function

This unit is compatible with the Caller ID service offered by your local telephone company. To use this feature, you must sub-
scribe to a Caller ID service. The data for the caller ID from the telephone exchange is sent during the interval between the
first and second rings of the bell signal. The data from the telephone exchange is a modem signal which is modulated in an
FSK (Frequency Shift Keying) format. Data "0" is a 1200 Hz sine wave, and data 1 a 2200 Hz sine wave.
There are two type of the message format which can be received:i.e.the single data message format and multiple data mes-
sage format.
The multiple data format allows to transmit the name and data code information in addition to the time and telephone number
data.
When there is multiple data in the unit, the name or telephone number are displayed.

2. Circuit Operation:

The caller ID signal input from TEL LINE is processed with IC5.
Refer to Sgnal Route (P.108) for the route of caller ID signal.

40

1. Function

This unit is compatible with the Caller ID service offered by your local telephone company. To use this feature, you must sub-
scribe to a Caller ID service. The data for the Caller ID from the telephone exchange is sent before the first ring signal. The
data from the telephone exchange is sent by DTMF signal.

2. Circuit Operation:

The Caller ID signal from TEL LINE is processed with MODEM (IC5).
Refer to Sgnal Route (P.108) for the route of Caller ID (DTMF) signal.