[aprssig] are write-only APRS-IS clients valid?

Tom Hayward esarfl at gmail.com
Sun Dec 1 21:51:05 CST 2013

On Sun, Dec 1, 2013 at 7:35 PM, Andrew P. <andrewemt at hotmail.com> wrote:
> Greetings, all.
> I've had what seems to be an odd request for a feature expansion to my APRS
> client YAAC, and I want to make sure it's sane before I implement it.
> I've had more than one user ask how to configure my client to be a
> write-only client to APRS-IS, that is, relaying RF-received packets to
> APRS-IS, but refusing to accept any traffic back for possible relay back to
> RF. I've seen a lot of receive-only IGates on the map, but how does one tell
> the APRS-IS servers that a given Igate does not accept traffic for relay to
> RF? Having a write-only GUI client seems to be a little strange (as in, why
> not use aprx or some similar daemon-style client instead of a GUI client
> like YAAC?).

This breaks two-way messaging. The APRS-IS assumes that the igate that
gated a position packet for a station can also relay a message to that
station. In RX-only igates, this assumption is false and the
message/ack may not reach its recipient.

I believe there are jurisdictions where it is not legal to run a
tx-capable igate (UK maybe? I don't recall). For these users, I would
suggest not connecting the PTT line to their TNC.


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