Net 44 and Icom Terminal Mode

Since before the days of the commercial internet, amateur radio operators have had their own Class A block of IPv4 addresses. Net 44 or AMPRNet is a non-routeable amateur radio experimentation network and access is only available to licensed radio amateurs around the world.

While hams have been experimenting with Net 44 since the early days of packet radio, interconnecting RF and wired networks via AX.25, I’m a relative newcomer. A couple members of the 020 Team are up and running on the AMPRNet and looking at potential use cases.

My driving use case is the to get around the limitation of one ircddbgateway behind a single network address translation (NAT). This limitation prevented me from running an ircddbgateway to service my Pi-Star hotspots and to use Icom Terminal Mode on my IC-9700 at the same time. What is the limitation? UDP port 40000, used by the ircddb protocol, must be forwarded to the destination system. As the Highlander said, “There can be only one.”

By establishing a Net 44 subnet behind my firewall and assigning a Net 44 address to the Icom, I get around the single IP NAT limitation. There’s a bit more to this, but a Net 44 gateway can be run on a spare Raspberry Pi or your internet gateway router (or any Linux based host). This article is not, however, meant to be an implementation guide but more of a starting point for thought.

It is also an announcement that XLX020 is now available on the AMPRNet for use by those with Icom Terminal Mode radios. Our gateway address on the AMPRNet is and you can connect to any module using a To Call of /XLX020m (replace m with your module of choice). If you’re on Net 44, feel free to connect.

73 de K2IE

Icom Terminal Mode on XLX020

There’s an exciting new development in the XLX reflector world. XLX reflectors now officially support Icom Terminal Mode. If you’re not familiar with terminal mode, it allows you to communicate with the DSTAR world via the internet from your radio. No separate hotspot or dongle is required and since RF is not used, no antenna either.

Terminal mode is supported by the newer Icom radios, including the IC-9700, ID-4100, and the Plus model HTs. If you have a radio that supports terminal mode and want to give it a try, set the host to

Thanks to Marius (YO2LOJ) for cooking up the code and submitting it to the xlxd project. It is great to see that the open source model is helping to advance digital amateur communications.

73 de K2IE