Model 28 ASR

RTTY.COscilliscope representation of MARK-SPACE signalsM

RTTY Model 28 ASR and KSR Machines

History of RTTY and Major Contributors - When and where and how it started, and how it advanced and changed over the years. Stories and short biographies of those individuals whose efforts advanced the hobby and made it better for others.

Introduction to Amateur Radio Teletype - By Irvin M. Hoff, K8DKC/W6FFC.   Mr. Hoff was an active radio amateur and a recognized authority in the field of amateur radio teletype.  Articles by Mr. Hoff have appeared in leading publications for decades providing major contributions to the technical advancement and increasing popularity of RTTY.

Teletype Story - The booklet 'THE TELETYPE STORY' was originally produced as a handout commemorating the 50th anniversary of The Teletype Corporation.

About RTTY.COM - An introduction to the Web Master and Co-Web Master who have been involved in RTTY for many decades.


Contact Us - If you have any questions about RTTY hardware or software or want to suggest improvements to this WEB site.



Bytheway Software Development Lab (BSDL) - wealth of software developed specifically for the RTTY enthusiast.

Kretzman Technical Library - Schematics, equipment manuals, adjustments, and other not-so-easy to find info. We have looked long and hard, spent many hours providing you difficult to find information on teletype machines, terminal units and other information needed to bring your RTTY gear back to life.

Baudot RTTY Frequency List - Current list of known RTTY broadcast frequencies.



Greenkeys - GreenKeys is a mailing list (reflector) devoted to the discussion of older radio teletype (RTTY) gear including mechanical teleprinters, terminal units, rolls of paper, gears, cams, wingnuts, paper tape, and anything else related to older RTTY gear.

LINKS - Other sites of interest, noteworthy suppliers, and places extraordinary.


Fun Stuff

Royer RTTY Art Pavilion - Dedicated to the memory of Don Royer, WA6PIR. A collection of Teletype art pictures collected over the years, most of them recovered from paper tape and converted from BAUDOT to ASCII.

Code-Card Corner - The wallets, toolboxes, tech manuals and window corners of TTY repairmen invariably had Type-Box Charts, ASCII and BAUDOT code bit charts, etc. Here are some for you to enjoy.

Instructional Videos - A collection of YouTube videos showing you various teletype machines in action.



Model 14 Reperforators

Model 15 KSR

Model 19 Teletypewriter Set

Model 28 KSR

Model 28 ASR

Model 28 Extended ASR

Tactical Teletypewriter Set (MITE)

Model 32




Demods & Terminal Units

Alltronics Molel-A (1955)

W5HFZ-W5RJG RTTY Converter (1955)

Mainline TT/L FSK Demodulator (1964)

Mainline ST-3 Demodulator (1970)

DT-500 and DT-600 Demodulator made by DATA TECHNOLOGY ASSOCIATES, INC (1977)

Mainline ST-6 Demodulator (1970)

Mainline UT-2 Demodulator (1975)

Basic first release ST-5 (1970)

Updated ST-5 (1973)

Frederick Electronics 1632 Demododulator (1976)


Teletype Frequency Shift Converter Model K


Service & Maintenance

Western Union Field Tech Service Manual - 168 Pages of info on the care and feeding of the Models 28 and 35 ASRs.  This was a compact-sized Technical Manual issued to Western Union Field Technicians as a handy aid in the maintenance and lubrication of Model 28 and Model 35 ASR Sets.

The Teletype Stunt Box Book - All about the Model 28 Function/Stunt Box

Critical Tuning - RTTY.COM is pleased to present BSP Section 570-001-901, which is a compendium of Critical Adjustments for the most commonly found Teletype Equipment from Model 14 to Model 35.

Teletypewriter Maintenance Tools Tools -- A very late edition (AUGUST 1977) of the Teletype Corporation Maintenance Tools Catalog.

Our Mission

RTTY.COM has been established to focus on the many aspects of Amateur Radio Teletype (RTTY) and to present to the dedicated RTTYer, and to the curious, a location wherein one can find information relating to RTTY and BAUDOT communications.

Anyone and everyone who has ever had any interest or participation in Amateur RTTY is encouraged to frequent this website. Your comments and suggestions are solicited so that the best possible utilization of this website can be implemented. 

The YouTube video to the right demonstrates a Model 28 teletype machine copying news bulletins being transmitted by the 24/7 Internet service provided by RTTY.COM.  Read on for more information about this interesting service being offered teletype enthusiasts.

Our RTTY over Internet Services

We offer Internet teletype broadcast services which can be received using software on your computer.  Click Here for Instructions on how to Listen to FSK Teletype Signals News and Features Updated Periodically 60 WPM 5-unit Code - 2125 Mark - 2295 Space

The following two links introduce you to an online Internet service provided by RTTY.COM.  Clicking on a link will bring up your computer's default sound player, usually Real Player or WinAmp. 


The video on the right shows an example of how to use this service.  NEED SOMETHING FOR YOUR MACHINES TO PRINT???


ITTY - Alive and Active

Streaming audio link to the RTTY.COM server, should bring up your default software on your computer, usually RealPlayer or WinAmp
General News Bulletins via Internet broadcasted 24/7.


Internet Teletype Greenwich Channel
Keep a watch for this feature to be added in the near future.


Streaming audio link to the RTTY.COM server, should bring up your default software on your computer, usually RealPlayer or WinAmp
When you listen to the AUTOSTART channel you will not hear the familiar RTTY tones until a message is posted. 

George Hutchinson. W7TTY

This was the original site that has been in service for 17 years and was operated by George Hutchison, W7TTY.

George has now officially announced his retirement as of 21 November 2017.

Paul Heller, W2TTY

George, W7TTY has been working with Paul, W2TTY for the last half decade transitioning ITTY from Sequim, Washington to Arvada, Colorado.  Welcome Paul as the new chief engineer.

l Bytheway, K7TTY

Bill, K7TTY was the original developer of all of the software used for ITTY. 

For more info go to

SDF Public Access UNIX System




Many thanks to for providing us with the opportunity to provide the http://RTTY.COM services for many years. 

George Hutchinson madly typing away for the next broadcast. This is how I usually see him, asses and elboes! Paul Heller 
You Are Visitor #
Bill Bytheway
Bill cringing at the possibilities for next changes to the WEB site.

Copyright 2020 RTTY.COM Last modified: 27 July 2020