Initializing Circuit - Panasonic KX-TMC40JX-W Service Manual

voltage appears at the Tip (T) and Ring (R) leads (When the telephone rings), the AC ring
voltage is transferred as follows:
T L101 R2
When the CPU (DSP) detects a ring signal, Q103 turns on, thus providing an off-hook condition
(active DC current flow through the circuit) and the following signal flow is for the voice signal.
T D101 Q103
R.
ON HOOK Circuit:
Q103 is open, Q103 is connected as to cut the DC loop current and to cut the voice signal. The
unit is consequently in an on-hook condition.
SPECIFICATIONS
In the on-hook state (idle), the current flows between the telephone line and the unit is as
follows:
T L101 R2
The DC component is blocked by C2, C3: thereby providing an on-hook condition.
The AC interface impedance is over 100k
requirements.

9.16. Initializing Circuit

Function:
This circuit is used for to initialize the microcomputer when it incorporates an AC adaptor.
Circuit Operation:
The set can operate beyond point A in the circuit voltage diagram.
C2 Q1 IC201 pin 27.
R119 C110
C2 R4 C3
R117 R116 D103
R2 L102 R.
; thus, satisfying the telephone company
D101 L102 P0S101