As far as I know, no one has got
a pair of these surplus units to operate.
This is another voice security
device used with radios like the
PRC-77.
This
box has an identical function as the
KYV-2,
KY-38 or
KY-57
Transmission Encryption Devices, although it uses a different
algorithm.
In order to use it two things need to be accomplished:
(1) a key needs to be loaded into one or more of the 8 slots.
There are a number of key loaders for the U.S.
crypto boxes including the CV-4228
PC to SINCGARS fill cable. This fill cable uses the
RTS and DTR lines to generate the Clock and Data streams
(NOT the transmit data line which has no clock). This
method is much simpler in terms of hardware, but more
complex in terms of software than building a custom key
loader for the MSC-2001.
A very simple cable could be made by wiring the RS-232
outputs from RTS and DTR directly to the clock and data pins
on the MSC-2001. No active parts are required and the
same software that drives the CV-4228
could be used.
(2) an interface needs to be used between the MSC-2001 and the
radio.
Vehicle
The KY-57 is used with the J-3513
Junction Box that interconnects the KY-57, radio, DC
power supply, and Vehicle Inter Communication (VIC) equipment or wire line
adapters. The J-3513 (or the smaller
J-3514) might also work as the interface between the
MSC-2001 and the rest of the system?
Manpack
It may be that just a cable could be used between the
MSC-2001 and a PRC-77, like the CX-12991/U between the
KY-57 and PRC-77. The pin assignments on the MSC-2001
strongly suggest this is the case. Although the cable is NOT
a 1 to 1, it's close.
There are two main printed
circuit boards using through hole components. The boards
appear to be double sided with the bottom traces generally
going left to right and the top traces going up to down.
A 40 pin IC (probably a micro processor) is in a socket formed
using 40 individual sockets. Nearby are what appear to
be a couple of ROM chips.
There's also 5 daughter printed circuit boards which use
surface mount technology and have been painted red. Four
of these red boards have 3 or 4 each ICs with 6 leads, most
likely op amps. None of them have any higher pin count
chips so they most likely are analog processing.
Another larger daughter board has a couple of pot core type
inductors/transformers and has the feel of a switching mode
power supply. It has a
74S40
Switching Mode Power Supply controller IC rated at 1.5
Amps and 100 kHz.
There's a couple of green wire wrap wires soldered to the
bottom of one of the printed circuit boards indicating a "fix"
was needed.
The 3.4 Volt "AA" size battery in this unused unit was
completely dead (0.0 Volts).
There's a lot of 14 pin 14xxx series CMOS ICs: MC14001 Quad
2-Input NOR gate, MC14013 Dual Type D Flip-Flop, MC14015 Dual
4-Bit Shift Register, MC14024 7-Stage Ripple Counter, MC14025
Triple 3-Input NOR Gate, MC14035 4-Bit
Parallel-In/Parallel-Out Shift Register, MC14066 Quad Analog
Switch, MC14070 Quad XOR and NOR Gates, MC14519 4-Bit AND/OR
Selector or Quad XOR, MC14572 Hex Gate, and some other chips
near the 40 pin IC.
There are two connectors, both of which are the same as the
POWER connector on a PRC-77 radio. One is labeled REMOTE
and may be used in an aircraft installation to control the
MODE selection of which code to use. The other connector
is marked TX/RX and is the interface to the PRC-77 or other
wide band radio. The REMOTE connector is also used for
loading up to 8 keys.
The Tx/Rx connector has the following pins connected to the
same letter pin on the REMOTE connector: A, B, C, D, E, F,
J. On my unit with the front panel switch, I see no way
the REMOTE connector can control the channel selection.
Maybe it does on the other version. The REMOTE does have
the key load connections which are not on the TX/RX connector.
The MODE switch has 8 channel positions for different keys
plus positions for CLEAR speech and CODE ERASE. The
switch has no mechanical stops and can be turned completely in
a circle. There's a thin plastic disk on the switch
shaft under the knob that has a pointer sticking out past the
diameter of the knob. If the switch is turned either
clockwise or counterclockwise to the CODE ERASE position the
thin plastic disk breaks into two pieces. If this
happens you can use acrylic cement (solvent) to fix the disk.
The 10 position
Grayhill
-
Series
71
(marked
on back 81073) switch has only 5 wires connecting it to
the rest of the MSC-2001. This is a 1, 2, 4, 8 binary
switch. The black wire is ground, Violet is 1, Orange is
2, Yellow is 4, and Green is 8. Decimal position 0 is
labeled 1, position 7 is labeled 8, position 8 is labeled
CLEAR and position 9 is labeled CODE ERASE.
There are 2 connectors on the
MSC2001 one labeled Tx/Rx used for the radio interface and one
labeled Remote that's used for either key loading or for
connection to other equipment, like the
AM-2060 or the
MK-456 retransmission kit.
This table is my best guess as to what the pinout is.
You can see the MSC2001 was designed with the PRC-77 in mind.
Pin
|
H-250
|
PRC-77
|
MSC2001 Tx/Rx
|
Linked
|
MSC2001 Remote
|
A
|
Gnd
|
Gnd
|
Gnd
|
=
|
Gnd
|
B
|
spkr
|
Aud
out
|
Aud
out |
=
|
Aud
out |
C
|
PTT
|
PTT
|
PTT
|
=
|
PTT
|
D
|
Mike
|
Aud
in
|
Aud
in |
=
|
Aud
in |
E
|
-
|
+15
in
|
+15
in |
=
|
+15
in |
F
|
-
|
Batt
+15
|
Batt
+15 |
=
|
Batt
+15 |
H
|
-
|
nc
|
PTT?
|
=
|
key
CTS in
|
J
|
-
|
Mike
gnd
|
Mike
gnd |
=
|
Mike
gnd |
K
|
-
|
retrans
PTT
|
nc
|
x
|
-9
out
|
L
|
-
|
tone
dsbl in
|
tone
dsbl in |
x
|
key
clock in
|
M
|
-
|
nc
|
Aud
out
|
x
|
key
RTS out
|
N
|
-
|
sw
+10 out
|
+12
in |
Note
1
|
+12
in
|
P
|
-
|
Rx-X-out
|
X
out
|
x
|
key
data in
|
R
|
-
|
Tx-X-in
|
X
in
|
x
|
key
RTS in
|
Note 1 - Both "N" pins are DC inputs that are joined by diodes
so either one will power the MSC2001, yet the DC can not be
fed from either.