Radio End	Battery End	Key Load Side	Standby battery cap	SVM on PRC-126

Table of Contents

Background

The military has a need for secure communications.  These fall into two general catagories: Voice and Data.
The method of encryption depends on the channel used.  For VHF voice communications the VINSON comsec system has been in place for a number of years.  The more popular crypto boxes for this system are the TSEC/KY-57 for ground equipment and the TSEC/KY-58 for airborne applications.  The TSEC/KYV-2 and -2A were designed to implement VINSON on the PRC-68 series squad radios.  The system also is known as SAVILLE.
Example of  TSEC/KY-57 sound. (random noise).

The KY-57 sends a synchronization header at the start of each transmission.  The radio operator should hear beeps when the crypto box syncs.  There is no provision to hear a clear transmission when the SVM is installed on a radio.  i.e. if the radio operator hears a voice when the SVM is installed the only way is if the transmission is encrypted.  This will prevent mistakes.

When the SVM was developed the PRC-68 and PRC-68A were in service.  The Magnavox part number for the SVM is 705293-801.  This is probably different from their part number for the KYV-2.

Since the TSEC/KYV-2 and 2A use the same algorithim as the KY-57/-58 then they use Continuously Variable Slope Delta-modulation (CVSD) to convert between digital and analog.

The SVM (same as TSEC/KYV-2) is the unit shown here.  The "A" version is about 2 inches long vs. the 3.5 inches for the original version and instead of a multiple PCB construction is made all in one module.  The "A" version weighs only 9 oz. compared to the 14 oz for the original.

When the SVM is used the battery life is cut in half with either the KYV-2 or -2A.

The SVM (KYV-2)  is a self-contained solid state unit consisting of four directly interconnected printed circuit boards (PCB) enclosed in a wrap-around aluminum case.  The TSEC/KYV-2 must be disassociated from the AN/PRC-68 or AN/PRC-68A for plain text communications, since there is no receiver plain text override capability.  The TSEC/KYV-2 will store only one cryptographic variable at a time.

SVM TSEC/KYV-2A.  The SVM, TSEC/KYV-2A is interchangeable with, and is the follow-on for the SVM, TSEC/KYV-2.  The SVM, TSEC/KYV-2A is a nonreparable, self-contained, solid-state unit that consists of only one PCB formed within a module and enclosed in a wraparound aluminum case.  It will not appreciably decrease the AN/PRC-68 or AN/PRC-68A battery life.  It is about one and one half-inch shorter than the SVM, TSEC/KYV-2.  Operationally and functionally they are the same.

On MCO 2040.10 the Marines ordered over 2,800 SVMs and less than 20 TS-13 test sets.  This is an interesting read with info about the PRC-68 and PRC-68A as well as some description of the KYV-2 and KYV-2A.

VINSON is also used in the KY-57 ground and KY-58 airborne voice encryption devices as well as in the Internal COMmunications (ICOM) security upgrade to the SINCGARS RT-1523 radios which are now current.

BANCROFT is used with the KY-67. TSEC/KY-67 and TSEC/KY-67A, Speech Security Equipment, Half-Duplex, Wideband, Tactical, and Ancillary Devices

Operation

I think that the KYV-2() (aka SVM) can be programmed at the depot level without any radios with a standby battery to hold the key and with the switch on the KYV-2()  in the ON position.  If there is a need to zeroize, the hold up battery and main battery are disconnected THEN the switch can be set to OFF or Zeroize.  In this way the key generator and fill gun do not need to be near a combat area.

The radio battery can be changed without loosing the key in the KYV-2() because of the standby battery.

Problem with Tx B+ not brought out to the SVM connector on some PRC-126 radios.
When trying to use the SVM-68, the PRC-126  radio transmits a carrier, but NO voice of any kind with the SVM-68 switch in either position.  The radio with a SVM-68 installed does not receive another station.

7 May 02
When used on a PRC-68 (that does not have the jumper options that are on the PRC-126, -128, -136 and probably the 68B and 68A, the transmitted signal sounds like noise on a receiver and on a spectrum analyzer looks like wide band modulation.  Much wider than a normal voice signal.  When a carrier with 150 Hz modulation is received the PRC-68 w/SVM makes a buzzing noise and when the 150 Hz is stopped (press INCR on the PRC-126 used for transmission) the PRC-68 w/SVM has a light background hiss (not a normal noise type hiss).

Another SVM owner's SVM test jig for working with the SVM to see why it does not work with the PRC-126.

When a 2.9 kHz signal (Sine, Triangle, Square, Ramp) is feed into the PRC-68 w/SVM the audio is a strange sound.  With 1, 2, 3 or 4 kHz you do hear the tone.  The literature on the SVM says that there is no clear speech capability on the SVM, but maybe that does not apply to an SVM without any key loaded?

Warning

Do NOT connect the SVM to a 15 Volt battery with the SVM switch set at "OFF Z".  This shorts out the internal power supply to drain the caps and also shorts out the main radio battery.  Not a very good design.

Caution

Not only does the SVM draw a lot of current when in use (cuts battery life in half) but it also draws a few milliamps when the radio is OFF.  Be sure to remove the main battery when the radio is off so you will not come back to a dead battery after a short storage time..

Problems

I have heard from a reliable source who says he saw a dumpster filled with KYV-2() Secure Voice Modules that were destined for destruction.  There are a few references in the open literature saying that the PRC-68 family of squad radios are not capable of secure voice operation.  For some reason the KYV-2() seems to have been recalled.  If you know please email brooke(at)pacific(dot)net.  I have found some problems:

• When used with the PRC-68 with no key installed you can communicate between two radios.  This would be a bad thing if an enemy had a captured KYV-2() also without a key.  This is not a problem with any of the other squad radios so may not be that big a deal.
• The Key Load connector on the KYV-2 uses a nonstandard pin out that is not compatible with the key load connector on the common fill devices like the KYK-13, KOI-18, KYX-15 and the CYZ-10.  The logistics nightmare that this would cause may be the real problem.
• There is no plain text override capability.  If a secure net was in operation and a friendly lost the key (maybe a low hold up battery) then they would be out of communication.  The SINCGARS radios have the ability to hear unencrypted voice.  This is a very important consideration.

Radio Compatibility

Although all the radios in this series (-68, -68A, -68B, -126, -128 and -136 have a connector to support the use of the SVM (KYV-2(A), the SVM does not work on all of them without some special configuration.  By "works" I mean that a digital signal is transmitted.
 

PRC-68	PRC-68A	PRC-68B	PRC-126	PRC-128 LB	PRC-128 HB	PRC-136 HB
works	works	works	works	carrier only no Tx cipher	no pwr on*	no pwr on*
				Rx 1 kHz tone very weak

*It appears that the SVM will NOT work with the VHF High Band (130 - 173.9875 MHz) modules in the PRC-128 and PRC-136.  This makes sense since the VHF High Band radios do not have enough bandwidth to support the 16 k bits per second digital data.  When the radio is turned on the LCD does not display anything.  There must be code in the microcontroller that does not allow the SVM to be used with high band RF modules.

The PRC-128 with a Low Band Module was not functioning correctly, on Tx only a carrier was there and on receive a 1 kHz tone was very weak, whereas a 1 kHz tone normally is heard OK with the SVM installed and operated with no key, as are all tests so far as of 18 May 2002.  There is a jumper inside the PRC-128 AF/SYNTH module that is related to SVM operation, but so far I don't know it's purpose.

26 May 2002 - It appears that when an unkeyed SVM is used with the PRC-126 the digital modulation sense (polarity) is reversed from what is used when a key is in the SVM.  This causes the receiver to not lock up.

I have heard that you can communicate using two unkeyed SVMs, but need to wait for my second SVM to arrive to test this.  It might require using two PRC-68 model radios?

8 June 2002 - Now have 2 each SVMs.  The serial number is prefixed by "E" indicating an engineering unit.
When an SVM is attached to a PRC-68 and PRC-68A you can talk from the PRC-68 and hear the voice on the PRC-68A, but not the other way around.  This is with no key loaded into the SVM.

If the receiving radio has the squelch disabled you hear noise when there is no transmission and when a transmission is received the radio quiets just like when no SVM is installed.

I think this is bug in the PRC-68, allowing the SVM to be used without a key installed.

28 April 2004 - Can't get clear voice when using two SVMs on two PRC-68 radios.
Also can't repeat the experiment where a PRC-68 can talk to a PRC-68A?
Also can't repeat the experiment where using SQUELCH DIS shows quieting?
The spectrum analyzer confirms digital data is being sent on all setups, so the SVM is connected and working.
Maybe need the Hold Up Battery?  One of the SVMs has a 3 zinc air cells, but one is dead, and the other SVM has no HUB.

Key Load Connector (J2) on KYV-2/2A

• A - positive power supply from Key Loader to allow key loading when no +15 battery is attached to the SVM (not sure of voltage yet)
• B, C, D - data, clock and Transfer Request from Key Loader (which is which?)
• E - internal battery voltage, about 4.4Volts for three fresh 675 hearing aid batteries.
  Probably used to confirm the state of charge of the internal batteries.  This could be done without loosing a key.
  
• F - common ground

Stimulus Test

Key Loading

"Electronic key fill of the SVM's, TSEC/KYV-2/2A will be accomplished through the use of the KYK-13, Electronic Transfer Device, KYX-15 Net Control Device, the AN/CYZ-10 Data Transfer Device, or the General Purpose Tape Reader, TAMCN A8024." (KOI-18?)  This quote from MCO 2040.10 is confusing considering the pin out differences between the SVM and other devices that receive keys.  See the table below for differences between the SVM and the SINCGARS key load connectors.

Based on the published information about the MX-18290 wich was designed to load the SINCGARS radios the pin definitions for the MX-18290 probably are:
 

pin	MX-18290 P1	MX-18290 J1	SINCGARS Function	Handset function	Probable SVM Function
A	J2-18	J2-18	Ground	ground	power from key loader if  SVM not on a radio at time of key load
B	nc	nc	na	Earphone (audio from radio)	Clock to SVM
C	J2-1	J2-1	Fill Request from radio	PTT (gnd to talk)	Fill Request from SVM (triggered from PTT?)
D	J2-6	J2-6	Fill Data to the radio	Mike (audio to radio)	Fill Data to theSVM
E	J2-16	J2-16	Variable rate clock to radio	na	HUB monitor
F	nc	nc	na	na	ground

The definitions of pins C and D may give a clue as to the functions of the same pins on the  KYV-2() Secure Voice Module Key Load Connector.  But the SVM uses pin A to receive DC power from the key loader so that it can be programmed when not attached to a radio.  The SVM uses pin E to monitor the Hold Up Battery and pin F as common ground.  So it looks like the 18290 can not load the key into the SVM unless a special cable was used.
 

10 Feb 2003 - Note The KYK-13 is referred to as the VINSON fill device. The KYV-2() SVM use of pin F instead of the common use of pin A for ground makes it a non standard application and may have been the reason that the KYV-2() was removed from service.  As far as I can tell in all other key fill applications pin A is the ground pin and is consistent with the AUDIO use of this connector.  Note on the SINCGARS radios the same connector is used for both AUDIO and key fill.

Note that typically the device receiving the key initiates the load operation.  This makes sense since the receiving device needs to be ready for the key download.  If the sending device initiated the download the receiver may not be prepared.

 
KYK-13 Interface - looks like the key is 128 bits long
FASCINATOR - approved for use with the  MCX-100, NX 300, Portable Repeater, SABER, SPECTRA, SYNTOR X-9000, SYNTO X-9000 E, Console Interface Unit, and SPECTRA Mobile SVMS. uses the KYK-13 and other key loaders
Security API from MSRC-5000SEC - for JTRS radios -
If the KYK-13 Electronic Transfer Device can be used then the KOI-18 Tape Reader should also work.
FM24-19 Chapter 4 indicates that the KOI-18, when loading a KY-57 has a parity check.  This may also be the case for the SVM.

Can the key be read from a keyed SVM? probably not,  other radios do not have this capability.

Is there a hardware handshake between the key loader and the SVM?  This might also be called an initiate command and a key accepted handshake.  To start the load the PTT is pressed on the KY-57, then how to initiate a load on the SVM?

If the SVM is attached to a radio then maybe pressing PTT would start the fill,
but if the SVM is being loaded without the radio maybe bringing pin A up to the power supply voltage would have the same effect.  If pin A was always high then just plugging the SVM onto the CSD-68 fill gun would start the key load.

EDO non NATO KY-57/58 equivalent Key Transfer Device, Key Fill Device, Voice Processor Unit
The Rockwell PLGR family of GPS receivers uses the KYK-13 for key loading or using the 988-3116-001  (NSN 599-01-450-9257) computer fill cable

Maintenance

Caution: Before removing the radio module cover be sure the SVM jumper plug is installed on the radio and not in the module cover pocket.  If it is in the pocket and you remove the module cover the fishing line will be broken.

Note: Before installing the SVM onto  a radio lubricate the threads on both the SVM and radio.

Caution:  When installing the SVM onto a radio the SVM housing should seat very close to the radio module cover.  If there is a big gap the SVM 15 plug may not be mating with the radio 15 pin socket.

The key parts of the SVM-68 are:
 
 

Box w/ flex circuit	Audio & power supply PCB	Digital PCB

• Box with flex circuit connecting the passive components (Wiring Table)

Note that J3-9 Radio SVM 150 Hz disable is at DC gnd as is J3-8 Radio SVM Gnd = SVM installed.
But J3-7 Radio SVM Squelch disable is dynamically pulled to ground by the SVM.  Why is this?
On Motorola encryption systems the Tx unit sends a 1 kHz tone at the end of transmission to tell the Rx unit to turn off the squelch, maybe this works the same way. (DVP web page)
• Rear analog Assembly Printed Circuit Board with 2 x 14 pin connector mating with box
• Front digital Assembly with large unmarked ICs and 2 x 8 connector to the Rear Assembly PCB

TI TL022 Dual Op Amp
TI TL044
Harris CVSD chip has analog in -> digital out and digital in -> analog out, encode/decode
• Test Equipment TS-13/TSEC is a go/no-go tester.  Publication SAM-65/TSEC

Battery

Memory battery 0.45" dia x 0.6" long (what is it?): maybe 3 each 675 Zinc Air hearing aid batteries?  The case & cap are negative ground. The positive end of the batteries goes into the battery compartment first,this is the flat end.  The 675 hearing aid batteries are a close fit and require good alignment then they just drop in.

Parts of the System

Maybe a PIC microcontroller can be programmed to load the key.

WANTED - information about the key length, headers, check sum, etc.  . . . . .  i.e. the format of the key. brooke@pacific.net

The MX18290 is used to fill the SINCGARS radio hop set and the hop set key, but not the KY-57 voice encryption box and will not work for the TSEC/KYV-2/2A.

Details of the PRC-68 Interface to the TSEC/KYV-2/2A

The 16 kb/sec digital data is compatible with MIL-STD-188-220 the Estelle data link protocol.  Note that this is a much wider bandwidth than the 3 kHz used for plain voice.  16 kb/sec needs about 8 kHz bandwidth.  The claim is made that there is a 6 dB improvement in the radio due to the speech filter that would be a factor of 4 implying the encrypted speech is in a 9 kHz bandwidth.

          The 15 pin mating connector between the radio and SVM has the following terminals:
               1 - Tx Cipher (12 kHz) to modulator (possible future digital data interface?)
               2 - Gnd
               3 - Chopped B+ (generated by the battery saver circuitry)
               4 - Rx audio (3 kHz) to speaker or handset
              5 - Rx Cipher from receiver (12 kHz) (possible future digital data interface?)
               6 - Rx B+
               7 - Squelch Disable
               8 - Ground to indicate that a SVM is there (or digital data?) connects to J2-3
               9 - 150 Hz Disable (150 Hz is disabled for secure coms)
               10 - Gnd
               11 - On/Off Run B+
               12 - Tx B+ (this is necessary for proper operation and may be a jumper option on the PRC-126, -128, -136 and 68A, 68B?)
               13 - Gnd
               14 - Tx audio from microphone ( 3 kHz)
               15 - Battery B+

How does the radio detect that the SVM is installed?

The SVM connector pin J1-8 is labeled "secure voice or gnd" and is wired to Frame/Panel J2-3. This description is not correct since the SVM jumper plug has no contact in position 8, i.e. the jumper is open not ground.

On the other hand they don't mean secure voice = ground and normal operation is open, see below for the reason why.

On the PRC-128 RF/IF module J2-3 is marked NC and this is confirmed by the VHF low and high band schematics that show n.c. for J2-3.  The AF/Synthesizer module has J2-3 going to a two way jumper option and one of these connects J2-3 to a line labeled "secure voice detect (sheet 1 J) which goes directly to pin 37 of the microprocessor. This line has voltage clamping a diode drop away from 0 and +5 so it's a TTL line.  There's a 47 k Ohm resistor in series with the line going to the SVM pin 8 which is about right to pull pin 8 up or down or to sense if pin 8 is up or down.  (47 k Ohms is the shunt resistor value used on the AUDIO pin F (external data) and it allows two way communications on a single wire when grounded.)  More needs to be known about the capability of the microcontroller, i.e. can the output be tri-stated?  For sure pin 37 can act as either an input or output depending on what the program directs it to do.  The 47 k Ohm series resistor and the two clamping diodes makes a fairly bullet proof way of allowing the uC to talk to the outside world and at the same time protect it from electrocution in such a way that no damage will occur for over voltage with either polarity.  (The AUDIO pin F (ext. data) pin has a 1 k Ohm resistor in series with uC pin 28 with +5 and 0 volt clamping diodes.)

There is a 1 M Ohm resistor to ground on the uC side of the 47 k Ohm series resistor in the secure voice detect line.  This would cause the uC to see a ground when no SVM were present so having the SVM ground pin 8 to indicate it's presence would not work.

P2-18 (Tx cipher) could also be connected to either of these lines but why? (maybe Tx cipher can be routed to 1-J "secure voice detect" and directly into the microprocessor for digital data?

Another possibility is that there is some provision for a factory test mode that works through the SVM connector.

The illustration below shows the top of the SVM with only a 15 pin connector to mate with J1.  No battery snaps, so pin 15 feeds battery power to the radio whose battery snaps are in the air (not connected to anything).

Jumper Plug on PRC-68 series radios

The PRC-25/-77 have a connector marked "POWER" that also has a jumper plug attached when not using the crypto equipment  The jumper only routes DC power, not any audio signals.  If the jumper plug is removed from a PRC-25/-77 then the internal battery is disconnected and the radio needs to be powered through the POWER connector by the external equipment.

Zeroize

The SVM has an OFF (Zeroize) switch that shorts out the main power supply (main 15 Volt battery) and should only be swithed to OFF (Zeroize) when the SVM is seperated from the battery and the hold up batteries have been removed for the SVM.  Be very sure the switch is in the ON position before connecting the SVM to a battery.

Saville algorithm

Cypris - multi algorithm RISC processor Saville has 3 modes of operation
JTT P3I Security - Saville is a family of algorithims
Windster (Standard Embeddable Module) - supports "SAVILLE I and PADSTONE algorithms"
Indicator (Standard Embeddable Module) - "incorporates the SAVILLE I and PADSTONE algorithms."
Crypto Equipment Guide - "WINDSTER is a 500 Kbps full/half duplex embeddable COMSEC module used to secure digital voice or data traffic. It provides cryptographic interoperable traffic operation with KY-57/58, E-DRZ, KYV-2, KYV-5, KG-84, RAILMAN, INDICTOR, and STU-III. It also provides re-key operations interoperable with the KY-57/58, KYV-5, INDICTOR, and RAILMAN equipment.
AF Communications , C3 & C4 Systems Security Glossary - mentiones both Saville and VINSON
NISS Infosec Glossary  -  Saville Advanced Remote Keying (SARK)

F91100 BER Test Set

In order to test the Bit Error Rate of radios using the TSEC/KY-57 and other voice scramblers the Marines had a test built to measure the actual BER over real radio links.  This test set appears to be built in a box very similar to the TSEC/KY-57 and uses the same batteries as the PRC-68 family of radios.

Wire Line Digital Non-secure Voice Terminals (DNVT)

The current digital telephones use CVSD Continously Variable Slope Delta (MIL-STD-188-113 Interoperability and Performance Standards for Analog-to-Digital Conversion Techniques) the same as the common military voice scramblers.  These are also 16 kbps systems.
See: TA-1042 Digital Switch -

17 Feb 2008
Removed commas from patent numbers.
Changed patent links to USPTO stable format.

Theory

NSA -The Start of the Digital Revolution: SIGSALY Secure Digital Voice Communications in World War II - Although the patent application was filed in 1941 it was granted in 1976!  Secret telephony patent number 3967067 is the start of digital voice encryption.  "Speech component coded multiplex carrier wave transmission" patent number 3991273 filed in 1943 and awarded in 1976 covers the multilevel FSK method used to transmit the secret telephony.  Another secret telephony patent with a 1941 file date yet with a 1976 award date is patent number 3985958.  These are very old W.W.II methods referenced here for historical value.

SPEAK EASY RADC developed and certified SPEAK EASY AN/GSC-38(), a secure voice, digital communications system for use over standard telephone lines. The Center began work on the system in 1975. SPEAK EASY's high data-rate performance was consistent with encryption devices of the period. Initially tested and evaluated in March 1981, the 16 kilobit/second modem/VINSON Secure Voice Terminal was transitioned to ESD in June  -- whereupon it became known as "SPEAK EASY." AN/GSC-38( )
 

The primary AF-1 high level voice link is the secure UHF military tactical satellite voice system.  This provides two (on the 747s 28000
and 29000) (and one on the Gulfstream C-20's favored for shorter flights by Clinton) 16 kbs MSK CVSD secure digital voice circuits using Vinson KY-58 crypto gear (or some interoperable equivalent).

Walsh Code - is NOT used, KY-57/58 and -2 use CVSD Continously Variable Slope Delta to convert voice to digital data.

4052565 Walsh function signal scrambler -  - A digital speech scrambler system allowing for the transmission of scrambled speech over a narrow bandwidth by sequency limiting the analog speech in a low-pass sequency filter and thereafter multiplying the sequency limited speech with periodically cycling sets of Walsh functions at the transmitter. At the receiver, the Walsh scrambled speech is unscrambled by multiplying it with the same Walsh functions previously used to scramble the speech. The unscrambling Walsh functions are synchronized to the received scrambled signal so that, at the receiver multiplier, the unscrambling Walsh signal is the same as and in phase with the Walsh function which multiplied the speech signal at the transmitter multiplier. Synchronization may be accomplished by time division multiplexing sync signals with the Walsh scrambled speech. The addition of the sync signals in this manner further masks the transmitted speech and thus helps to prevent unauthorized deciphering of the transmitted speech. US Class 380/28

Calls:
3204035 - 370/208; 375/362 Orthonormal Pulse Multiplex Transmissions Systems 26 Nov 1962
3678204 - 177/15; 370/209 Signal Processing and Transmission by means of Walsh Functions 26 Oct 1970 ITT (KY-38?)
3742201 - 708/410 Transformer System for Orthogonal Digital Waveforms June 26, 1973
3859515 - 708/410; 324/76.12; 324/76.21; 340/5.81; 382/121 Method and Apparatus for Signal Spectrum Analysis by Hadamard Transform Jan 7 1975 Burroughs

3618077 :WALSH FUNCTION GENERATOR -
3701143 :WALSH FUNCTION GENERATOR -
3795864 :METHODS AND APPARATUS FOR GENERATING WALSH FUNCTIONS -
5311176 :Method and apparatus for generating Walsh codes -

Post Vietnam KY-57, OTAR, SICGARS Patents

5428686 : Secure communication system having long-term keying variable -filed:  Sep 28, 1981

NSA patent about mixing a key held in the scrambler with a key sent over the air.
This is the idea for Black keys that can be used for Over The Air Rekeying (OTAR).

Calls:

3439279 - SYNCHRONIZING SYSTEM FOR RANDOM SEQUENCF, PULSE GENERATORS, Gustav Guanella, Zurich

Calls:
3028552 FREQUENCY SHIFTING CLOCK

3171082 RANDOM PERMUTATION GENERATOR EMPLOYING PULSE WIDTH GENERATOR AND CIRCULATING ...

3363183 SELF-CORRECTING CLOCK FOR A DATA TRANSMISSION SYSTEM

3781472 - Digital Data Ciphering Technique, Goode (Datotek), Dec 25 1973, 380/2 ; 380/44 -

Calls:
2951120 APPARATUS FOR DETECTING MALFUNCTIONS IN TELEGRAPH SYSTEMS
3522374 CIPHERING UNIT, Intl Std Electric Corp, Jul 28 1970, 380/260 ; 380/265; 380/43
2993089 ENCIPHERING AND DECIPHERING APPARATUS FOR SECRET TELEGRAPH SYSTEMS
2898402 MONITOR FOR A TELETYPEWRITER
2690475 SYNCHRONOUS TELETYPEWRITER MIXER
2897268 CIPHER TELEGRAPH SYSTEM
2406829 TELEGRAPH SYSTEM
3546380 CIPHERING AND DECIPHERING APPARATUS, Oskar Sturzinger Baar, Zurich, Dec 8 1970, 

3781473 - Random Digital Code Generator, (Datotek),Filed: April 15, 1971, Issued:Dec 25, 1973, 380/46

Calls:
3051783 APPARATUS FOR ENCIPHERING-DECIPHERING TELEPRINTER COMMUNICATIONS, Hell, Aug 28 1962, 380/47 - teleprinter system

Calls:
2785224 Enciphering Device, Kurt Ehrat, Zurich, filed: Aug 17, 1953
2874215 TWO-TAPE CIPHER SYSTEM, Teletype Corp, filed: Mar 23, 1955
2899498 APPARATUS FOR SYNTHESIZING FACSIMILE SIGNALS FROM CODED SIGNALS, filed: Nov 30, 1953 - Eastman Kodak Co

3038028 ARRANGEMENT FOR PRODUCING A SERIES OF PULSES, Telefunken, Filed Feb 7, 1958
3506783 KEY MATERIAL GENERATOR, Ivar Mo (Intl Std Electric Corp), Filed Jun 12, 1967

Calls:
3155818 ERROR-CORRECTING SYSTEMS, F. M. GOETZ (Bell Labs), filed May 15, 1961
applications: #  645315 & 645305 which are:
 3496291 ENCIPHERING TELEPRINTER TEXT FOR TELEX CHANNELS, (Intl Std Electric Corp)
3506783 KEY MATERIAL GENERATOR, (Intl Std Electric Corp), filed: Jun 12, 1967

3557307 CIPHERING MACHINE, Florin, Finland, AB Transvertex, filed: Mar 10 1969,
3170033 ELECTRICAL GENERATORS OF QUASI-RANDOM SYMBOLS,Vasseur, Compagnie Gen Telegraphie, Filed Jul 27, 1961

4052565 - Walsh function signal scrambler, filed: May 28, 1975 - Martin Marietta Corporation

4200770 - Cryptographic apparatus and method, Stanford University, filed: Sep 6, 1977 -Hellman, Diffie, Merkle

4316055 - Stream/block cipher crytographic system IBM, filed: Dec 30, 1976

Calls:
3657699 MULTIPATH ENCODER-DECODER ARRANGEMENT, Rocher, filed: Jun 30, 1970, 380/265 ; 341/81; 380/37; 714/701
3798360 KEY REGISTER, Horst Feistel (IBM), filed: Jun 30, 1971, 380/37 ; 380/29; 713/166
3958081 Block cipher system for data security, 178/22; 340/172.5

Prior Art References:
Substution wheels:
2964856 METHOD OF AND APPARATUS FOR CRYPTOGRAPHY, Albeit W. Small, Filed: Mar 10, 1941, Issued: Dec 20, 1960, 380/58

Note the 19 year delay in issuing the patent.  Rotor type.

2984700 METHOD AND APPARATUS FOR CRYPTOGRAPHY, Albert W. Small, Filed: Sep 22, 1944, issued: May 16 1961, 380/26 ; 380/44

Note the 17 year delay in issuing the patent. 

Shannon's paper in the Bell System Tech Journal Oct 1949.    Rotor type.
Stream Generators:
3250855 electrical Generators of Quasi Random Digits, Vasseur, filed: May 23, 1962, 380/42 ; 341/173; 380/46 - logic gates
3364308 Key Generators for Cryptographic Systems, Vasseur, filed: Jan 23, 1963, 380/44 - logic gates
Purmutation ciphers:
3522374 CIPHERING UNIT, Intl Std Electric Corp, Jul 28 1970, 380/260 ; 380/265; 380/43
3506783 KEY MATERIAL GENERATOR, Ivar Mo (Intl Std Electric Corp), Filed Jun 12, 1967 - see above)
Anti Jamming:
3411089 COMMUNICATION SYSTEM, Francis A. Gicca,  filed: Jun 28, 1962, Raytheon, 380/34 ; 375/285; 375/E1.034; 375/E1.036; 380/35 -

This may be the SINCGARS frequency Hopping system like used on the RT-1439
Calls:
2408692 SIGNALING SYSTEM, Henry Shore (RCA), Oct 1 1946, 380/34 ; 455/61 - multiple channels
2878316 MULTI-CHANNEL COMMUNICATION SYSTEM, Wilson P. Boothroyd (Philco), Mar 17 1959, 370/533 ; 375/240; 704/205 - FDM
2913525 SECRET COMMUNICATING SYSTEM, M. J. LARSEN (General Dynamics), Nov 17 1959, 380/276 ; 315/8.51; 380/36-

voice encryption using pulse amplitude modulation and purmutations (maybe KY-38?)
Calls 1920 to 1950 patents:
1369805
2089639
2313209
2364210
2401464
2401888
2403280
2406349
2467486
2486491
2508622
2527638

2965702 Television
3030450 BAND COMPRESSION SYSTEM, Bell Labs, filed Nov 17, 1958

Called by:
4181816 Devices for combining random sequences, using one or more switching operations, Jan 1, 1980
4349915 Minimization of multipath and doppler effects in radiant energy communication systems, Sep 14, 1982
4597087 Frequency hopping data communication system, Jun 24, 1986
4802220 Method and apparatus for multi-channel communication security, Jan 31, 1989
4866771 Signaling system, Sep 12, 1989

3188390 SIGNAL TRANSMISSION WITH SECRECY, Miltoa E. Meisr (Bell Labs), filed Dec 20, 1943, Issued Jun 8 1965

Notice 22 year delay in issue date.  divides up the audio spectrum into bands
reference app #  456322 SIGSALY related patents

3188390 SIGNAL TRANSMISSION WITH SECRECY   (Bell Labs)
3223931 MOHR IMPULSE PRODUCING CIRCUIT   (Bell Labs)
3340361 SIGNALING SYSTEM WITH CATHODE RAY TUBE QUANTIZER (Bell Labs)
3394314 CIRCUIT SUPPLYING IMPULSES OF REGULATED PEAK AMPLITUDE (Bell Labs)
3887772 SIGNAL PRIVACY WITH SAFETY FEATURE  (Bell Labs)
3897591 SECRET TRANSMISSION OF INTELLIGENCE (Bell Labs)
3934078 Key generating system (Bell Labs)
3953678 Speech component key signaling system with code combinations (Bell Labs)
3965296 Signaling system (Bell Labs)
3983327 Electrical signaling (Bell Labs)
3991273 Speech component coded multiplex carrier wave transmission   (Bell Labs)
4178474 Signaling system (Bell Labs)
4343970 Signaling system   (Bell Labs)

Product Ciphers:
3798359 KEY -EFFECT ROUTERJun 30, 1971  IBM
3796830 John Lynn Smith (IBM), Recirculating Block Cipher Cryptographic System, - DES
app 552685:

4195200 Key controlled block-cipher cryptographic system employing a ...Jun 30, 1976
3958081 Block cipher system for data security Filed Feb 24, 1975
4078152 Block-cipher cryptographic system with chaining Filed Apr 26, 1976
4074066 Message verification and transmission error detection by block chaining Filed Apr 26, 1976

Pseudo Random Code and XOR gate

Another possible implementation would be to use some type of pseudo random code generator and exclusive or it with a digital form of the voice signal.  This would need some type of header to sync the receiver to the transmitter.
3746799 :METHOD AND APPARATUS FOR ENCODING AND DECODING ANALOG SIGNALS -
4244053 :Privacy communication method and system -
3610828 :PRIVACY COMMUNICATION SYSTEM -
3651404 :VOICE PRIVACY ADAPTER -
4167700 :Digital voice protection system and method -
3639690 :DIGITAL PRIVACY SYSTEM -
4126761 :Method of and means for processing an audio frequency signal to conceal intelligility -
3909534 :Voice privacy unit for intercommunication systems -
3893031 :Synchronization system for voice privacy unit - A system for synchronizing the operation of two or more voice privacy units. At least one otherwise "clear" tone is modulated by a statistically random signal known as a Barker word, this tone then being mixed with the audio signals and transmitted. The modulation is present for a very short time, the conclusion of the modulation initiating the operation of a code generator which scrambles the succeeding audio signals. The recognition of the reception of the modulated tone at the receiver initiates the operation of its code generator (at the conclusion of the modulation), thereby recovering the original plaintext speech.
3766316 :FRAME SYNCHRONIZATION DETECTOR -
4268720 :Scrambler speech transmission and synchronization system -
4149035 :Method and apparatus for enciphering and deciphering audio information  -
3614316 :SECURE COMMUNICATION SYSTEM - An improved secure communication system comprising: A first and a second pseudorandom noise generator, said generators having,espectively, a first and a second shift register, each register having N stages and having logical circuit means for randomly recirculating binary bits through the register for generating a random repeatable pattern of binary bits, A reset pulse source coupled to all stages of said first register to reset said first register to a predetermined starting binary number, A starting point switch matrix comprising N logical zero-one switches connected, respectively, between the stages of said second register and said reset pulse source, Means for feeding a binary information number to said switches to reset said second register to a starting point a predetermined number different from the starting binary number of said first register, Transmitting means for transmitting said pseudorandom noise generators outputs connected to the outputs of said pseudorandom noise generators; Receiving means for receiving said transmitting means transmissions, said receiving means having an output; Recycling storage means connected to the output of said receiving means for storing the receiving means output signals; A third pseudorandom noise generator identical in sequence to said first and second pseudorandom noise generators having an output and a reset input, said receiving means output connected to said reset input; A correlator having a first input connected to said storage means and a second input connected to said third pseudorandom noise generator output for generating a signal upon correlation of said storage means output and said third pseudorandom noise generator output, and; Timing means connected to said correlator for timing the interval between outputs thereof.
4341925 :Random digital encryption secure communication system - combine two PR code streams
3808536 :COMMUNICATION SCRAMBLER SYSTEM - A scrambler system in which amplitude zero-crossings in speech are encrypted at a transmitter by combination with a pseudo-random digital sequence, the reverse process occurring at the receiver. The amplitude envelope need not be encrypted, but if desired, can be encrypted by combination with a further pseudo-random digital sequence. A higher level of scrambling can be achieved in the transmitted signal by using the conjugate of the amplitude envelope.  With a sequence bit rate of about two kilobits per second, there is no increase in bandwidth requirements compared to the transmission of unscrambled speech. Thus standard transceivers can be employed, and pre-existing ones readily modified for scrambling and unscrambling.

Links

KY-57

Real KY-57

KY-57 Trainer

Loading Secure Device - a KYK-13 or KYX-15 key transfer device is used to load the KY-57.

SpecwarGear.com - Communications - photos of the KY-57
USMC - information on using various crypto boxes including the KY-57
Pacific Forces COMSEC Procedure.pdf -
List of manuals at Ft. Gordon with KY-57 mentioned -

TM 11-5810-256-OP-5
Operating Procedures for Communications Security Equipment TSEC/KY-57
Retransmission. 12 May 1983

TM 11-5810-256-12
Operator's and Unit Maintenance Manual for Communications Security
Equipment TSEC/KY-57. 12 August 1993

TM 11-5810-312-12-1
Operator's and Organizational Maintenance Manual: Installation Kits for
Communications Security Equipment, TSEC/KY-57, Volume 1. 15 August
1982

TM 11-5810-312-12-2
Operator's and Organizational Maintenance Manual: Installation Kits for
Communications Security Equipment, TSEC/KY-57, Volume 2, Installation
Kits for Wheeled Vehicles.  8 September 1982

TM 11-5810-312-12-3
Operator's and Organizational Maintenance Manual: Installation Kits for
Communications Security Equipment, TSEC/KY-57, Volume 3, Installation
Kits for Tracked Vehicles.  15 November 1982

TM 11-5810-312-12-4
Operator's and Organizational Maintenance Manual: Installation Kits for
Communications Security Equipment, TSEC/KY-57, Volume 4, Installation
Kits for General Purpose Use and Shelter Applications. 19 April 1983

The  HYX-57/TSEC is not the KY-57 but is a radio to wire interface in a box very much like the KY-57.

McDowell Research - Power Supply and Adapter List -
USM 481 Test Set -
BB- 390A/U - NSN 6140-01-419-8187 is used in the KY-57
About NITFS Interoperability Testing... -
Communication Tips

90.Place a plastic cover over your PRC-77/KY-57, and wrap them in an additional waterproof bag.
95.Before a mission, always place fresh batteries into your communication gear and sensors, especially the BA-1372 memory battery for the KY-57.
96.Always carry spare PRC-77 and KY-57 batteries, but do not remove the spares from their plastic wrapping prior to use, or they may lose power.

The KY-38 voice security unit was designed to work with the MRC-108 FAC jeep, ARC-51 aircraft radio and VHF squad radios like the PRC-25 and is part of the Nestor family.
The corresponding airborne unit was the KY-28.

TCIM Family of Tactical Communication Interface Modems: Supported Protocols -

Modulation Mode                            Data Rate
KY-57/SINCGARS NRZ Digital       600,1200,2400,4800, and 16k bps
KY-57/SINCGARS NRZ IAW        16k bps

Russian web page - FM 24-24 Chapter 6 Section VI. Single-Channel Tactical Satellite Communications Radios

The AN/CSZ-1A Sunburst II processor provides high grade half-duplex secure voice and data communications over wideband and narrowband communications links. The Sunburst II supports both secure voice and secure data at 12 and 16 kb/s over wideband radio links. The unit also provides narrowband secure voice (LPC-10E) and secure data at 2.4 kb/s for radio or wire line transmission. The Sunburst II incorporates the indictor COMSEC module, and has been endorsed by the National Security Agency to encrypt voice and data up to the TOP SECRET level. Key features include ANDVT compatibility and the capability to receive OTAR in both narrowband and wideband modes. The Sunburst II provides the user with the capability to communicate to a host of existing COMSEC equipment such as KY-57/58 VINSON, ANDVT/KYV-5, KG-84 A/C, SINCGARS, Fascinator, STICS, and Sunburst I.
Appendix A Joint and Service Unique Networks -

Network/ Interface	Interface Type	nbsp;Interface Spec	Protocol	nbsp;Message Type
TACFIRE/(2-wire, 4-wire,  CNR, KY-57, KG-84,  DSVT, DNVT,  SB-3614A,SB-3865,)	NRZ  FSK-188B  FSK-188C STANAG 4202  CDP	MIL-STD 188-114A  MIL-STD 188-110  ACCS-A3-407-008C  STANAG 4202  MIL-S-29354  ITT-AOD-No.  337032004-2  TT-B1-4204-0028B  TT-A3-4001-0014 TT-C1-7205-0102  TT-A3-9013-0048B  TT-C1-7204-0099  CSESD-14G	Fire Support  IFSAS  IFSAS Enhanced  IFSAS Smart	ALL
MTS/(2-wire, 4-wire,  CNR, KY-57, KG-84,  DNVT, DSVT,SB-3614A,  SB-3865)	NRZ  CDP  FSK-188B  FSK-188C  STANAG 4202  MIL-188-110A	MIL-STD 188-114A  MIL-STD 188-110  ACCS-A3-407-008C  STANAG 4202  MIL-S-29354  ITT-AOD-No.  337032004-2  TT-B1-4204-0028B   TT-A3-4001-0014   TT-C1-7205-0102  TT-A3-9013-0048B  TT-C1-7204-0099  TT-B1-1201-0030B  CSESD-14G	MTS
Net Radio Protocol  (NRP)/ (2-wire, 4-wire,  CNR, KY-57, KG-84)	NRZ  CDP  FSK-188B  FSK-188C  STANAG 4202  MIL-188-110A	MIL-STD 188-114A  MIL-STD 188-110  ACCS-A3-407-008C  STANAG 4202  MIL-S-29354  ITT-AOD-No.  337032004-2  TT-B1-4204-0028B  TT-A3-4001-0014   TT-C1-7205-0102  TT-A3-9013-0048B  TT-C1-7204-0099  TT-B1-1201-0030B  CSESD-14G	Net Radio Protocol
Tank Net Radio Protocol  (TNRP)/ (2-wire, 4-wire,  CNR, KY-57)	NRZ  CDP  FSK-188B FSK-188C  STANAG 4202 MIL-188-110A	MIL-STD 188-114A MIL-STD 188-110  ACCS-A3-407-008C  STANAG 4202 MIL-S-29354  ITT-AOD-No.  337032004-2  TT-B1-4204-0028B  TT-A3-4001-0014  TT-C1-7205-0102  TT-A3-9013-0048B  TT-C1-7204-0099   TT-B1-1201-0030B  CSESD-14G	NRPT  NRPT(AWE)	ALL
IEWCOMCAT/ (2-wire,  4-wire, CNR, KY-57,  KG-84, DNVT, DSVT,  GRA-39)	NRZ  CDP  FSK-188B  FSK-188C  STANAG 4202 MIL-188-110A	MIL-STD 188-114A  MIL-STD 188-110  ACCS-A3-407-008C STANAG 4202 MIL-S-29354  ITT-AOD-No.  337032004-2  TT-B1-4204-0028B  TT-A3-4001-0014  TT-C1-7205-0102  TT-A3-9013-0048B  TT-C1-7204-0099  CSESD-14G	IEWCOMCAT

 

VDC-400 PCMCIA Data Controller - Compatible COMSEC Devices = AN-CSZ-1A, KY-57/58, ANDVT Tacterm, KY-99/99A/100, KG-84 A/C, KIV-7, STU-III

FAS - The TSEC/KY-57 will eventually be replaced by the Advanced Narrowband Digital Voice Terminal (ANDVT/Minterm, KY-99), when fielded.

Advance Logistics Order for the ST-58 Automatic Test Equipment

a.  Requirement.  The ST-58 ATE was designed to provide an automatic test capability for the VINSON, KG-84 () and common fill device families of communications security (COMSEC) equipment.  Its flexibility and modular construction allow for future expansion to incorporate additional COMSEC equipment testing capabilities.

Computer Security Solutions, Inc. - SMF-MR Fax -  STU-III, KY-57/99A, KY-68 (MSE), KG-84A/C, and TRITAC
Validation Demonstration Model.pdf -
Tactical MicroICE (Imaging & Communications Environment)  - The tactical protocol supports communications over COMSEC devices and radios like the SABER, SINCGARS, PSC-5, MSHR, KY-57, KY-58, KY-99, and KY-99A.

 
 Condor ESD - CESD’s wideband secure voice and data equipment (WSVE) upgrades existing UHF/VHF transceivers to a digital cryptographic voice and data communications system. . . . Electrical and mechanical interfaces ensure direct replacement for U.S. KY-57 or U.S. KY-58

Airterm ANDVT (KY-100) interoperates with TACTERM (CV-3591/KYV-5), MINTERM (KY-99A), VINSON (KY-57,KY-58) and SINCGARS.

Micro-internet Controller (µINC) Card  - Sample Interfaces: SINCGARS family of VHF radios, AN/PRC-138 (adaptive HF) radio, AN/VRC-12-series analog radios, AN/PRC-104 HF radio, AN/PRC-840 analog radio, KY-99 and KY-99A in narrow- and wide-band modes, KY-57 and KY-58 in wide-band mode (16 Kbps), ANDVT (CV-3591), KG-84C, HF modem, and HF radio

NITFS Baseline Documents - JIEO Spec 9137 Technical Interface Specification, National Imagery Transmission Format Standard, Tactical Communications Protocol (TACO2) to KY-57/58 Cryptographic Devices.

IDM: Ground Station & OPS Tester -

Crypto Equipment Guide - Windstar Standard Embeddable Module -

Endorsed TEMPEST Products List -

Common Ground Station (CGS)AN/TSQ-179(V)1

TASK: Operate AN/GRC-240 (VRC-83) Radio Set in a ground configuration.
CONDITIONS: Using an operating AN/VRC-83(V), AN/PSN-11, Radio set, TSEC/KY-57 Speech Equipment, loaded KOI-13/TSEC electronic Transfer Device with fill cable, SOI.

Effects of Tandeming on Voice Quality and Intelligibility -

Tandems occur whenever the output of one type of voice coder is used as input for a second coder. This happens when people using different types of coders need to talk to each other, for example, when a person using an ANDVT terminal running LPC-10 at 2.4 kbps wants to talk to someone with a VINSON KY-57 running CVSD at 16 kbps, or, in the commercial world, when a Bell Atlantic cell phone customer wants to talk to someone with a Sprint Spectrum cell phone. At reasonably high data rates, although voice quality does suffer somewhat, the consequences are not too awful. But tandems with low data rate voice coders lead to significant losses in intelligibility and voice quality.

DDVPC Test & Evaluation Committee -

The Continuously Variable Slope Delta-modulation (CVSD) algorithm attempts to reconstruct the exact waveform at the receiver that was input to the transmitter; thus it is classified as a waveform coder. The digital output from the transmitter is 1 bit per input sample upsampled to 16Kbps. The transmitted bit stream is used to indicate the slope of the input waveform. The slope-limiting detection logic looks at the 3 most recent bits transmitted.  If these bits are all 1's or all 0's, the step size is doubled. For all other combinations, the step size is cut in half. The ratio between maximum and minimum step size is 16.  The sign of the slope is positive if the current bit is a 1 and negative if the current bit is 0.

HF INDUSTRY ASSOCIATION -

NTISSC-113/87 Draft NTISSI Operational Doctrine for VINSON, BANCROFT,  KYV-2, and KYV-2A, Action 10-13-87

Harris Fidelis - Crypto IC - supports VINSON and KYV-2A/B
UTE-Monitor - NSA No. CSESD-14 is the spec for VINSON

Secure Telephone Units, Crypto Key Generators, and Scramblers - AN/CSZ-12 Satellite Scrambler, AN/CSZ-4 Tactical Sat-Com, TRC-762 Audio Scrambler, Datotek DLE-7000 Scrambler

Technical Communications Corporation bought Datotek - Technical Discussion On Voice Encryption Methods - the following TCC patents all appear to be analog methods as described in the Tech Disscussion.

5822430 System for encoding encryption/decryption information into IFF challenges
4433211 Privacy communication system employing time/frequency transformation
4392021 Secure facsimile transmission system using time-delay modulation - FAX
4276652 Secure communication system with improved frequency-hopping arrangement - variable BFO
4195202 Voice privacy system with amplitude masking -
4856063 No-overhead synchronization for cryptographic systems -

Datotek (TCC)

4349695 Recipient and message authentication method and system - two way pass & CRC at end
4278840 Dynamic frequency and time voice encryption system and method - analog
4229817 Portable electronic cryptographic device - alpha numeric digital keypad & display
4185166 Multi-mode digital enciphering system - digital: off line, asynchronous or synchronous data
4170714 Digital cryptographic system and testing thereof - digital data
4169212 Multi-mode digital enciphering system
4166922 Multi-mode digital enciphering system with repeated priming sequences
4140873 Multi-mode digital enciphering system
4133974 System for locally enciphering prime data - digital key generator using a register and addressable memory
4133973 Digital cryptographic system having synchronous and asynchronous capabilities
4115657 Random digital code generator - digital multiple registers with relativity prime lengths
4091423 Synchronous digital data scrambling system - digital data
4079188 Multi-mode digital enciphering system
4020285 Voice security method and system - analog
4013837 Voice security method and system - analog
3991271 Voice security method and system - analog

5787180 Method of connecting a scrambler or encryption device to a hand-held portable cellular telephone - mike and spkr connections
5278907 Analog scrambling with continuous synchronization -
Audio Samples -
Essentials of 2-way Radio Scrambling - all their models are based on various forms of frequency inversion.

5528693 Method and apparatus for voice encryption in a communications system
4167700 Digital voice protection system and method -
5146498 Remote key manipulations for over-the-air re-keying - based on modifying the current stored ket to make the new one
4893339 Secure communication system January 9, 1990

4754482 Method and apparatus for synchronizing encrypting and decrypting systems

5003599 In-band framing method and apparatus

5363376 Method and apparatus for synchronizing timing among radio ports in wireless communications systems
3920894 Pseudo-Random Parallel Word Generator

5455861 Secure telecommunications - using encryptation only over part of the comm path

5305384 Apparatus, system and method for transmitting secure signals over narrow spaced channels -300 Hz to 3200 Hz spaced 11.4 kHz
5852803 APPARATUS, SYSTEM AND METHOD FOR RECORDING AND/OR RETRIEVING AUDIO INFORMATION

3614316  Secure Communication System Oct. 19, 1971 380/47; 375/150; 380/34; 380/46 - dual PN codes mixed

eBay - SVM-68 5 each -

Cypher, Crypto and Security Links -

L3 - Key Loader -

MSC2001 Voice Encryption Unit

This is a similar unit that was made by Seimens in Germany and holds 8 keys.  There are plans for a keyloader for this unit that requires getting the clock signal from a serial port and feeding it into a "Keybox" that gets the clock and RS-232 data aligned properly and will load the MSC2001.  For use with mil radios that support wide band audio like the PRC-77.

These are for sale by Mike Murphy.

Page about the MSC2001 by Coby Phillips

Electronic Key Management System (EKMS)