TA-1042A/U Digital Nonsecure Voice Terminal (DNVT)

 Radio Room  15 Responses »
May 302013
 
TA-1042A/U Digital Nonsecure Voice Terminal (DNVT)

The TA-1042A/U is a member of the family of Digital Nonsecure Voice Terminals (DNVTs). Basically, this is a field telephone with a 4-wire digital interface to automatic telephone exchanges of the TRI-TAC family. The wireline interface can operate at either 16 or 32 kilobits per second. There is no embedded cryptographic capability, hence the term “nonsecure”.

Two TA-1042A/U field phones may be connected together with 4-wire field line (generally WF-16/U) and operated as plain field telephones, with power supplied by local batteries connected to the terminals on the right side of each phone. They may also be connected to a digital telephone exchange, and receive their power from the exchange over the 4-wire interface. They are not compatible with analog telephone lines, analog field phones, or civilian telephone exchanges. Earlier members of the DNVT family, such as the TA-954/TT, cannot be used without connection to a compatible telephone exchange (i.e., they can’t be used as simple field phones.

Chris Story K6RWJ and I have decided to take on a project to reverse-engineer the digital interface used by these telephones, and create an interface which will allow them to be used as VoIP phones. We have dubbed the project DNVT2IP.

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800 Hz Power for Navy Radios, Part 1

 Radio Room  4 Responses »
May 122013
 
800 Hz Power for Navy Radios, Part 1

I recently bought a Westinghouse GP-7 transmitter in the swap meet at this year’s annual West Coast Military Radio Collectors Group meeting, held in San Luis Obispo, CA at the beginning of May. This transmitter was made for use in Navy aircraft, and it requires 120 VAC 800 Hz power like other Navy radios of its era. Aircraft commonly use AC power at higher frequencies than our common 60 Hz “wall power” so that their transformers and motors can be lighter. The higher power frequencies allow transformers and motors to use less massive iron cores without magnetic saturation. 400 Hz power is now commonly used in large aircraft that require AC power supplies, but this transmitter was made before 400 Hz power became the standard. Unfortunately, it can’t simply be plugged into 60 Hz power. That would saturate the transformer cores, and then they would release their magic smoke and stop working.

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2013 MRCG Event After-Action Report

 Crypto Room, Radio Room, Spy HQ  5 Responses »
May 082013
 
2013 MRCG Event After-Action Report

Last weekend, the 18th annual meeting of the Military Radio Collectors Group was held in San Luis Obispo, California, at Camp San Luis Obispo’s NCO club. The event included equipment displays, presentations, field operations and a swap meet. I had a great time, and nearly every other comment I heard about this year’s meet was positive. I’m already looking forward to next year’s annual meeting, as well as the occasional field events we’ll probably have throughout the year.

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M-209 Simulator Update: Now with Key List Generator

 Crypto Room  Comments Off on M-209 Simulator Update: Now with Key List Generator
Apr 282013
 
M-209 Simulator Update: Now with Key List Generator

I’ve just released version 2013-04-28a of my command-line M-209 simulator. The major addition to this release is a new Python script which generates key lists with daily scheduled key changes. The generated key list collections include 365-366 plain-text key files which may be read, printed or loaded into my simulator, and plain text key lists for each month which may be viewed or printed. Also, if TeX typesetting software and some other related utilities are available, various PDF key lists will be generated for on-screen viewing or printing into either small or large booklets. Please note that I’ve changed the version numbering from the old major.minor format to a date-based format.

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Looking for some Input on M-209 Key Lists

 Crypto Room  2 Responses »
Apr 242013
 
Looking for some Input on M-209 Key Lists

I’m working on a Python script which automatically generates a year’s worth of M-209 keying materials, with daily key changes. I hope that this script and its output will be useful for future M-209 activities, and add a more realistic flair to them.

Now, the big problem is that I’ve never seen actual M-209 key lists. I’ve come up with a plain text format for individual key tables, which I think I picked up from one of the M-209 technical manuals. I know that individual keys were identified by two-letter sequences called “key list indicators”. I know that keys were intended to be changed periodically, possibly daily (or possibly more or less often depending on activity level, but I’m sticking with daily for my purposes). I’ve seen a training film in which an M-209 key list is consulted, but the video transfer of the film is too blurry to make out useful details.

From these details, I’ve inferred what I think a key list might have looked like. I’m hoping to get some input from other crypto enthusiasts about the formatting, wording, etc.

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Practical Use of the M-209 Cipher Machine: Chapter 5

 Crypto Room  11 Responses »
Apr 142013
 
Practical Use of the M-209 Cipher Machine: Chapter 5

This post is part of a series of posts describing practical use of the M-209 cipher machine. The series will cover operation of the machine, setting the cipher key, formatting of messages, ciphering and deciphering messages, dealing with transmission errors, practices to make cryptanalysis (code breaking) of messages more difficult, and generating new key tables.

This chapter covers recognition and deciphering of messages.

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Practical Use of the M-209 Cipher Machine: Chapter 4

 Crypto Room  Comments Off on Practical Use of the M-209 Cipher Machine: Chapter 4
Apr 132013
 
Practical Use of the M-209 Cipher Machine: Chapter 4

This post is part of a series of posts describing practical use of the M-209 cipher machine. The series will cover operation of the machine, setting the cipher key, formatting of messages, ciphering and deciphering messages, dealing with transmission errors, practices to make cryptanalysis (code breaking) of messages more difficult, and generating new key tables.

This chapter covers composition, encipherment and formatting of messages.

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Practical Use of the M-209 Cipher Machine: Chapter 3

 Crypto Room  Comments Off on Practical Use of the M-209 Cipher Machine: Chapter 3
Mar 312013
 
Practical Use of the M-209 Cipher Machine: Chapter 3

This post is part of a series of posts describing practical use of the M-209 cipher machine. The series will cover operation of the machine, setting the cipher key, formatting of messages, ciphering and deciphering messages, dealing with transmission errors, practices to make cryptanalysis (code breaking) of messages more difficult, and generating new key tables.

This chapter covers internal key settings of the M-209.

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Practical Use of the M-209 Cipher Machine: Chapter 2

 Crypto Room  Comments Off on Practical Use of the M-209 Cipher Machine: Chapter 2
Mar 242013
 
Practical Use of the M-209 Cipher Machine: Chapter 2

This post is part of a series of posts describing practical use of the M-209 cipher machine. The series will cover operation of the machine, setting the cipher key, formatting of messages, ciphering and deciphering messages, dealing with transmission errors, practices to make cryptanalysis (code breaking) of messages more difficult, and generating new key tables.

This chapter covers basic operation of the M-209.

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A Collection of M-209 Key Tables

 Crypto Room  Comments Off on A Collection of M-209 Key Tables
Mar 242013
 
A Collection of M-209 Key Tables

Inspired by the Enigma World Code Group page, I have created a collection of key tables for the M-209 cipher machine for use by collectors and cryptography enthusiasts. This publicly-available collection of key tables, much like the code sheets on the Enigma World Code Group site, provides a set of ready-to-use M-209 keying material for M-209 aficionados to use. Obviously, openly published key tables don’t provide any real security, but they can be used by hobbyists to exchange M-209 cryptograms without needing to generate and distribute keying materials first. These key tables can be used for educational and entertainment purposes.

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Practical Use of the M-209 Cipher Machine: Chapter 1

 Crypto Room  8 Responses »
Mar 232013
 
Practical Use of the M-209 Cipher Machine: Chapter 1

This post is part of a series of posts describing practical use of the M-209 cipher machine. The series will cover operation of the machine, setting the cipher key, formatting of messages, ciphering and deciphering messages, dealing with transmission errors, practices to make cryptanalysis (code breaking) of messages more difficult, and generating new key tables.

This chapter covers cryptographic basics to help you understand the machine.

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New Release 1.5 of M-209 Simulator Software

 Crypto Room  Comments Off on New Release 1.5 of M-209 Simulator Software
Mar 162013
 
New Release 1.5 of M-209 Simulator Software

I’ve made a new release of my M-209 cipher simulation software:

https://gitlab.com/NF6X_Crypto/hagelin/-/archive/hagelin-1.5/hagelin-hagelin-1.5.tar.gz

Yes, another release. They’re clogging up my front page. Anyway, this minor release adds a user-requested feature and makes another minor change.

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New Release 1.4 of M-209 Simulation Software

 Crypto Room  Comments Off on New Release 1.4 of M-209 Simulation Software
Mar 142013
 
New Release 1.4 of M-209 Simulation Software

I’ve made a new release of my M-209 cipher simulation software:

https://gitlab.com/NF6X_Crypto/hagelin/-/archive/hagelin-1.4/hagelin-hagelin-1.4.tar.gz

This release eliminates the specially-encoded trailer that older versions needed in the key files. It now deciphers the human-readable key table instead, and tries to tolerate minor formatting variations.

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Looks Like My M936A1 Works

 Motor Pool  2 Responses »
Dec 102012
 
Looks Like My M936A1 Works

Another collector is buying my incomplete M1022 shelter dolly carcasses to use the parts for a couple of creative projects. They’re a bit hard to move around in any case because they’re all missing critical parts like the drawbars, but we had to deal with the added complication that they were pushed out of the way with a bulldozer before my home construction project, and then I built a house between them and the driveway. So, extracting one of them yesterday was a job for my new M936A1 wrecker.

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1965 Kaiser-Jeep M543A2 5-Ton 6×6 Medium Wrecker SOLD

 Motor Pool, Sold  5 Responses »
Aug 272012
 
1965 Kaiser-Jeep M543A2 5-Ton 6x6 Medium Wrecker SOLD

9/29/2012: This truck left today for its new home! Here’s the old for-sale listing…

I bought this 1965 Kaiser-Jeep M543A2 5-Ton 5×5 Medium Wrecker back in 2001, and I’ve been using it as a yard crane ever since. It was never road-worthy since I got it, and I never found the time and energy to fix it up into the fine truck that it could be. Now that I just got a very nice M936A1 wrecker to replace it, I’m putting it up for sale so it can move to a new home where it can get the attention that it deserves. Read on for details!

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