[aprssig] WB4APR SK

[Steve Dimse]

> On Feb 9, 2022, at 12:17 PM, Peter Laws N5UWY <n5uwy at arrl.net> wrote:
> 
> Is there a proper, preferably extensible, APRS protocol document?  Bob
> was visionary, but it always seemed like he was adding things to the
> system without a plan.

There is a spec, created in 2000. It is not perfect, but we got most of it right.

http://www.aprs.org/doc/APRS101.PDF

Bob maintained pages with errata and changes on aprs.org.

The spec has a user-defined format, which allows a programmer to do almost anything after the first three characters, it has been rarely used.

Steve K4HG