Kenwood KCT-31 User manual

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Copyright 2006 by Kenwood Corporation. All rights reserved.
No part of this manual may be reproduced, translated, distributed, or transmitted in any
form or by any means, electronic, mechanical, photocopying, recording, or otherwise, for
any purpose without the prior written permission of Kenwood.
Disclaimer
While every precaution has been taken in the preparation of this manual, Kenwood
assumes no responsibility for errors or omissions. Neither is any liability assumed for
damages resulting from the use of the information contained herein. Kenwood reserves
the right to make changes to any products herein at any time for improvement purposes.

© 2000-2 PRINTED IN JAPAN
B51-8573-00(S) 1433
KCT-31
INTERFACE CABLE
SERVICE MANUAL
OUTLINE ................................................................... 2
FEATURES ................................................................ 2
TERMINAL FUNCTION ............................................. 2
INSTALLATION ......................................................... 2
PARTS LIST............................................................... 3
SCHEMATIC DIAGRAM ............................................ 3
PC BOARD VIEWS.................................................... 4
CONTENTS

2
KCT-31
OUTLINE/FEATURES/TERMINAL FUNCTION/INSTALLATION
OUTLINE
1. The KCT-31 is a RS-232C interface cable for LMR Mobile
radios, TK-780,880,980,981 and TK-785,885.
The 9-pin (D-sub) connector is connected to an external
RS-232C terminal.
The other end of the cable is connected to the internal
connector of LMR mobile radio.
Note: You cannot write a firmware with the KCT-31.
FEATURES
1. This KCT-31 has a RS-232C-TTL level interface circuit.
2. This KCT-31 does not require an external power supply.
3. This KCT-31 can be used up to 9600 bps.
4. Compatible with an ER terminal of DTE that has the voltage
6V or more.
D-SUB Connector
Pin No. I/O Port Name Function
1 I CD Carrier detect
2 I RD Receive data
3 O SD Transmit data
4 O ER Data terminal ready
5 - SG Signal ground
6 I DR Data set ready
7 O RS Request to send
8 l CS Clear to send
9 - CI Ring indicator
Red
Black
Yellow
Green
A
B
C
9
51
6
Fig. 1
INSTALLATION
Note: When the COM 1 is used, A connector is unused.
When the COM 2 is used, C connector is unused.
1. Bind the unused connector to the cable with a retaining
band as shown.
Red
Black
Yellow
Green
A
B
C
When the COM 1 is used.
When the COM 2 is used.
ABC
1MOCONSEYSEY
2MOCSEYSEYON
connector
TERMINAL FUNCTION
2. Make sure the unit's power is tuned off.

3
KCT-31
INSTALLATION/PARTS LIST/SCHEMATIC DIAGRAM
Note:
Enable the Serial Port function on the terminal.
Refer to the service manual of each radio or the help file that
came with the FPU (Field Programming Unit) for details.
1
2
A
B
3
4
6
5
CN6
CN1
CN2
CN4
CN3
A
B
7
C
Fig. 2
Fig. 3
PARTS LIST
∗New Parts. indicates safety critical components.
Parts without Parts No. are not supplied.
Les articles non mentionnes dans le Parts No. ne sont pas fournis.
Teile ohne Parts No. werden nicht geliefert.
Destination
KCT-31
Ref. No. Parts No. Description
Address New
parts
KCT-31
!
C1 C92-0601-05 ELECTRO 10UF 16WV
C2 C92-0712-05 CHIP-TAN 22UF 6.3WV
D1 DAP202U DIODE
D2 MA2S111 DIODE
IC1 NJM78L05UA BI-POLAR IC
IC2 TC4S81F MOS IC
Q1 2SC4116(Y) TRANSISTOR
Q2 DTC114YUA TRANSISTOR
Q3 DTA144EUA TRANSISTOR
Q4 DTC114EUA TRANSISTOR
R1 RK73GB1J223J CHIP R 22K J 1/16W
R2 RK73GB1J392J CHIP R 3.9K J 1/16W
R3 RK73GB1J103J CHIP R 10K J 1/16W
R4 RK73GB1J473J CHIP R 47K J 1/16W
3. Remove the upper case of the transceiver and lift the DC
cable bushing (➊) from the chassis.
4. Remove the pad as shown in figure2 (❷).
5. Insert the KCT-31 cable (❸) into the chassis (❹).
The wire retaining band (➎) must be inside the chassis.
6. Replace the DC cable bushing (❻).
7. Connect the KCT-31 to the TX-RX unit (A/2) as shown in
figure 3 (➐).
8. Replace the upper case.
SG
CD
DR
RD
RS
SD
CS
ER
C I
95
61
IC1
NJM78L05UA
OUT IN
COM
12
33
2
1TXD
CN1
RXD
SB
5V
VDD
OUT
IC2
TC4S81F
MA2S111
VSS
INA
INB
R4
47k
15
2
34
GND
4
Q1
2SC4116(Y)
10µ16
C1
+
D1
DAP202U Q2
DTC114YUA
R2
3.9k
Q3
DTA144EUA Q4
DTC114EUA
22µ6.3
C2
R1
22k
R3 D2
10k
SCHEMATIC DIAGRAM
Note:
The above modification has already been applied to the TK-
780/TK-880 transceivers with a serial number of 30200001 or
greater.
When using a COM2 port, replace the 47 kΩ(R675) chip
resistor on the TX-RX unit B/2 with a 4.7 kΩresistor.
Original New
47kΩ(RK73GB1J473J) =4.7kΩ(RK73GB1J472J)

4
KCT-31
KENWOOD CORPORATION
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U.S.A.
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6 Pin 7 Pin 8 Pin 9 Pin Q1
D2
R3
R4
C1
IC2
IC1
5 Pin
R1
C2
D1
Q2
R2
Q3 Q4
4 Pin 3 Pin 2 Pin
CN1
1 Pin
Component Side View Foil Side View
PC BOARD VIEWS