[aprssig] RE: APRS User Activity Bit

Bill Herrmann bherrman at spro.net
Wed Mar 9 15:10:23 CST 2005

> How many times have we seen someone trying to message to a digi
> or an object? "You there?", "Good Morning"

Well, the activity bit is only part of the answer. If you check the table
at the beginning of chapter 5 in the APRS spec (The one that says "APRS
Data Type Identifiers.") you'll see that messaging capability is one of
the things called out there too. My suspicion is that some of the client
software does not distinguish between those and should. Check "!" and "="
or  "/" and "@" for examples. Each pair means the same type of data but
specifies whether the station supports messaging capability.

Curt - We may want to add something to the client capabilities chart to
indicate whether program X distinquishes between stations that can

> Would there be any interest in connecting to a server that only
> handled stations with human intervention, Or, develop a port on
> an existing server that would only display symbols of stations
> you could actually talk to?

Seems like that might be an appropriate filter capability to add. (rather
than adding yet more ports)

Personally, I'd like to see APRS client software better distinguish
whether a station is message capable and possibly even warn you if you try
to send a message to one that isn't. (and I'm gonna have to look at the
various APRS applications that I have to see which do that as I don't


More information about the aprssig mailing list