[aprssig] Digipeater addresses/spec question

Alexander Sack pisymbol at gmail.com
Wed Jul 20 10:51:18 EDT 2011

On Tue, Jul 19, 2011 at 7:49 PM, Stephen H. Smith <wa8lmf2 at aol.com> wrote:
> On 7/19/2011 11:07 AM, Alexander Sack wrote:
> Hello:
> If that's the case, why do Source addresses require a SSID while
> Digipeater addresses do not?
> Not true!
> Any packet station regardless of whether it is a home station, mobile,
> digipeater, igate, or whatever, can either use, or not use, an SSID.   The
> sole purpose of the SSID is to allow more than one station to operate under
> the same callsign.
> Note that an SSID of -0 (zero) is the same as no SSID at all.

>From looking at packets over the air, I wholeheartedly agree which is
why the spec has me confused!

> For example:
> In the greater Los Angeles area, which I just left, there are at least 4
> digipeaters operating under the same callsign (N6EX) with various SSIDs.
> I run WA8LMF (no SSID) as my main mobile,
> WA8LMF-3  on my TH-D7 handheld APRS radio
> WA8LMF-13 as a two meter VHF digipeater/igate at the home station
> WA8LMF-2  (30 meter HF APRS over classic 300 baud HF packet)
> WA8LMF-63 (30 meter HF APRS over PSK63)
> Decades ago, before specialized APRS-specific hardware and software was
> available, SSIDs were used to determine what symbol (house, car, truck,
> boat, digipeater, etc) would be displayed on the recipient's map.  This
> usage is now obsolete, since the APRS-format position report can embed the
> control codes to cause the display of over 200 different symbols.

Yes I got that this from Bob's page on SSIDs (thanks).  But the spec
seems to insinuate that AX.25 Source addresses have SSID's which is
again the source of my confusion.

Btw, Stephen, can I confirm that digipeater addresses are either
SOURCE addresses or DIGI ALIASes (e.g. WIDEn-N)?


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