Model 28 ASR

RTTY.COscilliscope representation of MARK-SPACE signalsM
Dedicated to Amateur Radio Teletypewriter
Hobbyists and Enthusiasts WORLDWIDE

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.



Contact Information

This page is currently under construction.

Teletype hardware and mechanical issues

George has retired.  This position is open to any volunteers.


Internet Teletype (ITTY and Autostart Services)

Paul Heller, W2TTY



Software development and tools

Bill Bytheway, K7TTY



WEB Site related matters

Paul Heller, W2TTY




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)


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.

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

Copyright 2011 RTTY.COM Last modified: 21Nov2017