Ringer Circuit; Power Circuit And Redial Back-Up Circuit; Sending Circuit (Tx) - Panasonic KX-T2371MXW Service Manual

Telephone equipment

Hide thumbs Also See for KX-T2371MXW:

Table of Contents

12.3. Ringer Circuit

Circuit Operation:

The bell signal passes through C1 (R1)

supplying power to pin 1 of IC2.

The ring signal is output from Pin 5 of IC2, and its volume is adjusted in 3 steps (H-L-OFF) by

SW3 then impressed on the ceramic sound generator, and so is generated.

Output frequency is controlled by R2 and C3 following below formula.

Function:

This set is powered from the line. When it is an OFF-HOOK status, Tel Line

R14

pin 17 of IC1 (to become the power supply for IC1 speech network).

The voltage from the line is turned into a constant voltage by D6 and then supplied to the IC1 and

sending and receiving circuit of the set.

At ON-HOOK status the voltage from the line via R40, R5 is turned into a constant voltage by D8,

and then become power supply for IC1 (Pin17), and the redial Back-up will be done.

When a person talk through the Handset, the voice analog signal flow from the

mic

C20

R33

R38

C23

Tel line.

* Q9 and Q3 is an amplifier for the voice signal.

Table of Contents