[aprssig] Igate symbol documentation

[Robert Bruninga]

> About 2 or 3 years ago there was mention 
> on this list about using "I&" as the Igate 
> symbol, and quite likely other variants of 
> the diamond "Gate" symbol with overlays for 
> Satgates, etc. 

> I have been unsuccessful in finding this in 
> any documents, is it documented anywhere? 

The master APRS symbol list has shown it that way for nearly a
decade.  It also allows for an overlay R for receive-only
Igates, but I personally would prefer that all Igates where
practical be 2-way because that is their function, and is
fundamental for the APRS messaging system to work.

http://aprs.org/symbols/symbolsX.txt

The TCPIP symbol most people seem to use was intended for
TCPIP-over-ax25 packet networks.  

Bob, WB4APR