Panasonic Va-208 Key Telephone System Installation Manual

2.4 Interrupt tone control and interrupt tone output. 
By the interrupt tone control data is sent to TEL from KSU, @ status is output on ICI pin NO. 23,then the 
receiving SW at busy IC5 (pin No. 1, 2) is turned to ON at the @ status on IC5 (Analog switch). 
The interrupt tone is sent to speaker by the following sequence: 
ICI pin No.27 + 05 (Amplify) + lC5 (Analog switch) pin No. 1 + ICI pin No. 2 + IC6 (Amp.) + Speaker. 
2.5 Speaker (SP) receiving control. 
When depressed speaker receiving switch, ICI...

4. A-K Communication 
Data communication between KSU (CPU) and TEL (APU) 
R4 
PTl 
C6 
H 
: _^ _ 
- 
I I 
=14. P30 
= I3 P23 
iI5 P31 
=3IRO 
-cB. PF2 Ic; 1 
I 
4.1 Receiving of A-K communication (ICI pin No 13). 
The input data from H, L line is received by ICI via the sequence of: 
PTI (Data induced) + R9 + 03 + IC3 pin No 6 (The data eliminated DC current by C5 and C6). 
NOTE: D2 is half wave rectifier. 
ICI pin No. 15 is receive the data from KSU only when the @ status is appeared on the A-K...

n TROUBLE 
SHOOTING GUIDE 
OPE RATI ON DEFECTIVE PHENOMENON 
CHECK ITEM 
VA-20810 
Service check 
Power SW ON 
t 
Don’t flashing on LED L3 
(1)Clock circuit 
(2)Timer circuit point- 1 
(3)ICl WR (Page-21) 
Off-hook the handset 
No Intercom dial tone 
(1) H,L power 
(2) A-K communication 
(3)Link IC control Service check 
point- 2 
(Page-Z) 
I I 
/ 
Call from TEL 1 
to TEL 2 No intercom incoming 
call tone (1) A-K communication 
(2)Link IC control Service check 
point- 3 
(Page-24) 
Can not intercom...

Service Check Point-l 
Don’t flashing on LED L3 (Green) Timer circuit 
r 
6 R35 
D1 _-9 77i? 
INT (W) Interrupt control 
data output CKHQ 
IC 1 
(CPU 1 
m (R) Read-out control 2 
data output 
Clock circuit 
~_~~~~~~~~~~~_-~ 
I x 1 ClOp, 
I I 
r 
IC4 
12 
-IN Hl 
Ii 
(1) Check of clock circuit 
(2) 
Does it input to ICI 
(pin No. 6) with following 
wave form? Check of timer circuit 
Does it input to ICI 
(pin No. 16) with follow- 
ing wave form? (3) Check of ICI W/R 
Does it output to ICI 
(pin No. 22)...

Service Check Point-2 
No intercom dial tone 
HE1 
TEL’ 
communication 
C26q I 2 - 
12 
INHi 
RST INH2 
10 Input data 
contra I 
I I 
4 A-K communication 
input 
IC 5 
I 
4 
A 3 
2 
1 40 
IC 6 
39 
10 
37 
(1) Check of the voltage between H and L 
(3) 
Does it 
output 12V between H (+) and L(-)? 0 
(2) Check of the A-K communication data input/output 
1) Does the data input to HBI (pin No.41 from TEL? 
2) Does the data output to TEL from HBI (pin No.~)? 
3) Does the data from TEL output on HBI (pin No. 1...

input/output wave form check for the A-K communication data 
(1) HBI (4pin) (2) HBI (3 pin) 
Measured with Smsec. 
2V and 50msec. range Measured with 2msec. 
and 2V range 
(3) 
HBI (11 pin) 
(4) Ic5 (4pin) 
T 
T 4.h 
4.8V 
JL 
_.__ _._ __._ ---- ---_ --_- 
Measured with 5msec. 
and 2V range Measured with 20msec. 
and 2V range 
(5) IC4 (13 pin) (6) HBI (IO pin) 
___._ ._-._.__ T 4.8V 
__._. _.... _..__ ___.- L 4.8V 
I I 
lk ____ _.._ _ ---.. ---.. AL 
Measured with 5msec. 
and 2V range 
(7) HBl (12 pin)...

Service Check Point-3 
No intercom incoming call tone . . . . . In case of the A-K communication of TEL1 is normal 
* In case of the call from TEL1 to TEL2 
(I) Does the data from KSU output to TEL2 when the call from TEL1 to TELP? 
Does it output? 
Measured with 2msec. and 2V range 
(2) 
Does the control data from IC6 output to ICI0 when call from TEL1 to TEL27 
Does ICI0 connects TEL2 and Tone unit? 
, Cross point 
Q201 
Does it output intercom 
incoming call tone? 
TEL 2 
L - ------) 
Can it be input...

Service Check Point-4 
Can not intercom conversation . . . . . In case of the A-K communication of TEL1 is normal 
* In case of the conversation between 
TEL 1 to TEL2 
(I 
) Does the answering data output to KSU when TE L2 called from TE Ll and TEL2 is answered? 
Does 
it output? 
L I Measured with 5msec. and 50m\; range 
(2) Does IC9 connects TEL1 and TEL2 when TEL2 is answered and the control data is sent from to IC9? 
,_e 
Cross point (4) 
I’ 
/’ 1’ -t Cross point 
(0) 
I I 
I I I 
I I i...

Service Check Point-5 
No CO incoming call . . . . In case of the A-K communication of TEL is normal 
* In case of COLI 
(1) Does CO incoming call data input to IC4 (pin No.40)? 
r’ -- 
CO incoming call-l 
i 
- 
signal 
L -- 
2 
) Does it output? 
(2) Does the control data output from IC6 to ICI0 when the CO incoming call data is input to IC4 (pin 
No. 4O)? 
In case of TEL1 programed to be sounds. 
1 4 
r-j I , sA 
3 ICI0 
I I 
2 I I 
I I 
1 I 
I I 
IC6 40 
I I 
39 I I 
I 
I i 
4DO I f 
/ 
Cross 
/’ 
I...

L 
Service Check Point-6 
Can not answer to CO call. . . . . In case of the A-K communication of TEL is normal 
* In case of answering on TEL1 
(I ) Does the data output to KSU when TE Ll is answered to CO incoming call? 
Measured with 5msec. and 50mV range 
(2) 
Does R Ll operates by the answering of TELI? 
I 1 
t 
Dbes RLI operates with 0 status? 
Does it output 0 status? 
(3) 
Does IC6 output the control data to ICI 1 by answering on TELI? 
Does ICI1 connects the conversation between TEL1 and COLI?...