What is IRLP in Amateur Radio?

What is IRLP in Amateur Radio?

If you go through the RepeaterBook entries, you will note that many of the repeaters are linked to IRLP, in addition to EchoLink, AllStar, D-STAR etc. So what is this IRLP? It is the Internet Radio Linking Project, which links amateur radio stations across the globe using Voice over Internet Protocol (VoIP). Gateways of IRLP have a dedicated computer running a Linux based software which connects the amateur radio to the internet and is known as an IRLP node. A specialty of IRLP is that end users still communicate using radios and not the computers directly. The motto of IRLP is “Keeping the Radio in Amateur Radio”! IRLP was designed by VE7LTD, David Cameron from Canada.

A radio amateur can initiate connection with any other available IRLP node across the world. A unique four digit identification number is there for each node and the current status of the nodes is available online at https://status.irlp.net/. When I checkded on 19th July, 2023 23:37 UTC, there were 2471 nodes in the United States and a varying number in 26 other regions. The web page also shows how many are in use, idle, offline and down. IRLP connections could be node to node or node to reflector. IRLP reflector is meant for stations wishing to communicate with 3 or more nodes at the same time. Most reflectors have 10 channels, numbered 0 to 9. There is a unique identification number for the reflectors, ranging from 9000 to 9999. While the first three digits represents the reflector number, the fourth digit represents the channel number. Currently there are 29 reflectors across various parts of the globe.

The computer to be used for IRLP should have a basic parallel port running LPT1, in addition to sufficient processing speed, RAM, dedicated hard drive, sound card and ethernet (LAN) adaptor, according to the information available at https://www.irlp.net/, which was updated in May 2023. IRLP software is currently running on Debian, an open source Linux project, with only about 500 MB on the CD and installs into about 2 GB on the hard drive. The radio to be linked or the repeater must have a carrier operated squelch signal. An IRLP interface board, cables and connectors are also needed.

There is also a PiRLP or IRLP on a Raspberry Pi, with an IRLP node on Raspberry Pi. This was possbile after a 2012 modification so that IRLP can use General Purpose Input/Output (GPIO) pins to communicate with the IRLP board instead of a parallel port.