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Panasonic Va-208 Key Telephone System Installation Manual

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Page 131

(3) 
(4) 
(5) 
1) Intercom call tone sounds and intercom voice call. 
When the intercom call sounding signal and voice call signal is sent to the TEL from the KSU, pin (36) of ICI 
becomes @ level. The @ level-signal is sent to pin (5) of IC5 via D4 and turns IC5 to ON. The following opera- 
tion is the same as in clause 2.2. 
Interrupt tone control and interrupt tone output. 
The interrupt tone control signal is sent to the TEL from the KSU, pin (23) of ICI becomes @ level, then the 
receiving SW at...

Page 132

1.4 A-K communication 
Data communication between KSU (CPU) and TEL (APU) 
+5v 
T---i R4 
c5 
Lo +H 7 
” - 
PTi 
(I) 
(2) Receiving of A-K communication 
(pin NO. 13 of ICI) A4 P30 
= I3 P23 
:I5 P31 
= 3.iKi 
K=. PF2 
The receiving signal from H and L line is received by ICI via the following path. 
PTI (Signal induced) -+ R9 -+ Q3 + IC3 (6) 
NOTE: 
DC current is eliminated by C5 and C6. D2 is a half wave rectifier. 
Pin (15) of ICl receives the signal from the KSU only when the @ level-signal appears...

Page 133

1.6. Transmitting circuit (speakerphone) 
R20 
AnA 
-tw 
Q6 
RI9 
When the SPKR button is pressed, pin (20) of ICI on the main P.C.B. (PB3942) becomes (@ causing Q5 and 06 
to be turned ON and the power to be supplied to the MIC. 
The send voice signal is connected to the COL via the following path. 
MIC -+IC6-+ IC2-+VR2’lCl +Tl -+COL 
In addition, the send voice signal is also input to the Voice SW via the following path. 
MIC+ IC6+ IC2-+VR2-+ ICI +Voice SW 
If there is any receive signal, since the...

Page 134

1.7 Receiving circuit (speakerphone) 
Sendvoice signal 
P 
vss 
I SP AMP 
I R50 I 
_L 
c55 7 R45 ICI 
I I IC4 
I 
I c4 I 
R2”’ , A6 _ 
r-v--i_ 5+ R3 +av 
The received voice signal is connected to the speakerphone via the following path. 
COL + ICI + VRl + IC2 -+ CN5 (8), Main P.C.B. + IC6 + Speakerphone 
In addition, the received voice signal is also inputted to the Voice SW via the following path. 
COL + ICI + IC4 + ICI + Voice SW 
If there is any send signal presente, pin (13) of IC2 (Voice SW) goes 0...

Page 135