aprx was originally a receive-only APRS iGate software, now extended to
do digipeating, and Tx-iGate. It works on any UNIX-like systems with
minimal requirements of system services, or system libraries beyond
basic POSIX libc.

The software is to be installed on a suitable UNIX-like system, and its
configuration file is then to be adjusted. Then it can:
* Handle arbitrary number of radio modems connected to itself
* Optionally relay APRS packets from radio receivers to APRS-IS
  (http://www.aprs-is.net) network
* Optionally digipeat AX.25 packets with and without APRS NEWn-N
  paradigm rules
* Optionally relay APRS packets from APRS-IS network to radio channel
  (Tx-iGate)

This software is intended for very limited resources environment, like
small embedded-like machines barely able to run the operating system
with TCP/IP networking.

A receive-only Rx-iGate does not need any sort of licenses in most parts
of the world where radio amateur hobby is permitted to begin with.

On version 2, aprx has gotten the ability to do APRS Digipeater
function, Aprx Tx-iGate, as well as a variation of that called Viscous
APRS Digipeater, which is an excellent choice for a Fill-In digipeater
like on a mobile station. Viscousness means that it will listen for
other copies of same packet for a small configurable number of seconds,
and if it hears same packet only once, it will do normal digipeating for
it.

aprx can optionally be used with soundmodem in place of a hardware TNC.