Version Control¶

AUTOMATIC PACKET REPORTING SYSTEM¶

APRS PROTOCOL REFERENCE¶

Protocol Version 1.2¶

This is an independent compilation, not affiliated with the APRS Working Group.

Version 1.2 – Unofficial Compilation¶

APRS is still alive and well a quarter of a century later, with many new products, computer applications, and creative uses. Many corrections, clarifications, and additions have been made to the APRS protocol specification since APRS101.PDF was originally published. All of these updates were documented separately and informally, rather than being merged into this document.

• http://www.aprs.org/aprs11.html
• http://www.aprs.org/aprs12.html

Implementation is more difficult and error prone with the information scattered around. Some people, trying to implement APRS, might not even know there were any updates. This is a compilation of the original specification and all of the relevant updates since 2000.

This is not endorsed by the APRS Working Group. The position of the APRS Working Group is that the “official” version is the original APRS101.PDF and Bob’s version of the errata on his site.

John Langner, WB2OSZ, editor.

April 2024

Version 1.0 Published by Tucson Amateur Packet Radio Corp 8987-309 East Tanque Verde Road, #337 Tucson AZ 85749-9399 United States of America

http://www.tapr.org

Originally edited by Ian Wade Copyright ©2000

APRS Working Group All rights reserved Version 1.2 edited by John Langner, WB2OSZ APRS® is a registered trademark of Tucson Amateur Packet Radio (TAPR). WinAPRS™, MacAPRS™, X-APRS™, PalmAPRS™ and APRS/CE™ are trademarks using the APRS® name, licensed from Bob Bruninga.

This document may be copied for non-commercial purposes only, and must include the above copyright statement and trademark statements in full.

Document Version Number¶

Except for the very first public draft release of the APRS Protocol Reference, the document version number is a 3-part number “P.p.D” (for an approved document release) or a 4-part number “P.p.Dd” (for a draft release).

Thus, for example:

• Document version number “1.2.3” refers to document release 3 covering APRS Protocol Version 1.2.
• Document version number “1.2.3c” is draft “c” of that document.

Release History¶

The release history for this document is listed in Appendix 7.

Document Conventions¶

This document uses the following conventions:

• Courier font ASCII characters in APRS data.
• _ Explicit ASCII space character.
• ... (ellipsis) zero or more characters.
• / $ Symbol from Primary Symbol Table.
• \ $ Symbol from Alternate Symbol Table.
• 0x hexadecimal (e.g. 0x1d).
• All callsigns are assumed to have SSID –0 unless otherwise specified.
• Yellow marker (appears as light gray background in hard copy). Marks text of interest — especially useful for highlighting single literal ASCII characters (e.g. " ") where they appear in APRS data.
• Shaded areas in packet format diagrams are optional fields.

Feedback¶

Please address your feedback or other comments regarding the unofficial 1.2 DRAFT of this document to John Langner, WB2OSZ. (callsign at arrl.net)