Kenwood TK-5210 Modification Information page 8

2 CONNECTING THIRD PARTY OPTIONAL DEVICES
2.1 Voice Scrambler Board
An optional board, such as a Voice Scrambler board, can
be installed in the transceiver. This section describes
how to install the Transcrypt SC20-460 in the transceiver.
Items Required for the Installation
• Transceiver
• SC20-460
• Cushion Tape (G13-1974-04) x 2
• 5 cables (AWG 30 wire is recommended.)
Remove the battery pack to install the optional board.
2.1.1 Configuring and Modifying the
SC20-460 Board
1. Prepare the SC20-460 board.
2. Modify the SC20-460 board and change the Receive
Audio Input method.
Note: If the Voice Scrambler board (KW21) for Kenwood
products is used, the modification is not required. Go to
step 5.
On a typical Voice Scrambler board, the transceiver
inputs the Receive Audio signal before De-
emphasizing the signal.
However, in this case, the transceiver inputs the
Received Audio signal after de-emphasizing the
signal, so that the Voice Scrambler board must be
modified.
• Cut the foil between E52 and E53.
• Solder between E51 and E52 to connect them.
• Solder between E53 and E54.
4
Contents
Note:
This modification can be also performed by using the
Transcrypt TR-3060 modem. In this case, change the value
from 0 to 1 at the address M1:3. It is not necessary to
modify the hardware of the Voice Scrambler board (SC20-
460).
The described modification must be done to avoid problems
such as low-level audio from the speaker or the presence of
loud and distorted noise.
Refer to the Voice Scrambler board's instruction manual for
details.
3. Change the components to meet the requirements of
transmit/ receive audio level.
• Change the following components, R1 to 18k
Ω
to 120k and C1 to 2700 pF to meet the
requirements of the Receive Audio level.
• Change the following components, R2 to 12k
R4 to 18k Ω
Transmit Audio level.
Before modification
Ω
R1, R3: 100k , C1: 0.1
(Default value of the SC20-460)
Ω
R2, R4: 100k
(Default value of the SC20-460)
4. Cut the cable to the appropriate length to allow the
wires to be dressed and soldered.
A length of approximately 50 mm is suitable.
1/8"
(3 mm)
5. Remove the Optional Board Connector PCB.
Remove the Optional Board Connector PCB and peel
off the cushion tape from the board. Refer to "2.1.2
Installing the Voice Scrambler Board in the TK-5210"
on page 4.
Confidential
Default
E51
E52
E53
E54
to meet the requirements of the
After modification
µ Ω
R1: 18k
F
Ω
120k , C1: 2700 pF
Ω
R2: 12k
2" (50 mm)
MOD (K)/Ver. 1.04
After
Modification
E51
E52
E53
E54
Ω
, R3
Ω
and
, R3:
Ω
, R4: 18k
1/8"
(3 mm)