APRS Connect

KISS server

The KISS server lets another program use APRS Connect as its TNC. The other program connects to a port on your computer over KISS on TCP, the same way it would connect to any network TNC. It hears what your channels hear, and what it sends goes out on them.

It is in the Windows and Linux apps, and needs APRS Connect Pro. The phone apps and the browser do not have it.

This is the other way round from a Network TNC channel. There the app connects to a TNC somewhere else. Here other programs connect to the app.

What works with it

Any program that speaks APRS to a KISS TNC over TCP. A second copy of APRS Connect works too, on a phone or another computer: add a Network TNC channel there and give it this computer's address.

Programs that need connected-mode packet, such as a BBS, do not work with it yet. The server carries APRS packets only.

Set it up

  1. Open Radio and choose KISS server.
  2. Turn on Run the KISS server. The line under the switch says which port it is on.
  3. Address for the other program is what to type into the other program. For a program on the same computer that is 127.0.0.1:8001.
  4. In the other program, add a KISS TNC over TCP. Some programs call it a network TNC or KISS TCP. Enter the address and the port.

When the program connects it is listed under Connected programs, with how many packets were passed to it and how many of its own were sent.

The server keeps running while the window is closed to the tray, and stops when APRS Connect is quit.

Port

Most programs expect port 8001, and that is what the server uses unless you change it.

If another TNC program is already running on this computer, it may have that port, and the page then says Port 8001 is in use by another program. Close that program or choose another port. The server takes the port as soon as it is free.

Who can connect

  • This computer is the default. Only programs running on the same computer can connect.
  • My network lets other computers and phones on the same network connect as well. The page then also shows this computer's address on the network, such as 192.168.1.20:8001. The system's firewall may ask once whether to allow it. On Windows, allow it on private networks.

KISS has no password. Anything that can reach the port can transmit through your station, under any callsign it likes. Leave it on This computer unless another device needs to connect, open it only on a network you trust, and never forward the port from your router.

Channels

Choose which channels connected programs hear and send on. Everywhere is every channel, including one you add later. Or pick the ones you want, radios and APRS-IS alike.

What a program hears:

  • A packet heard on a radio is passed on as it was heard, with its path. A copy that arrives again through a digipeater is passed on too.
  • A packet from APRS-IS is passed on as a third-party packet from your station, which is how APRS marks traffic that came from the internet. A program that is also an IGate does not send it back to APRS-IS as something heard on the air.
  • What APRS Connect transmits itself is not passed on, as with any TNC. A program sees your own beacon when a digipeater repeats it.

What a program sends goes out on every chosen channel that is connected and can transmit, under the program's own callsign and path. A packet whose path has NOGATE or RFONLY stays off APRS-IS.

Turn off Programs can transmit to let programs listen only.

A packet is not sent if its callsign is a placeholder such as N0CALL, which is what many programs are set to when first installed. Set your callsign in the other program first.

TNC settings that a program sends, such as TX delay, are ignored. Each channel keeps the settings on its own page.

Activity and the packet log

Activity lists the packets that connected programs sent, newest first, with the channels each went out on, or why it was not sent. Choose one to open it in the packet log, where it has a KISS mark. These packets are not counted as your own on the Dashboard.

If a program will not connect

  • Check that the port in the other program matches the one on the page.
  • From another computer, Who can connect has to be My network, both have to be on the same network, and the firewall has to allow APRS Connect.
  • If the page says the port is in use, another TNC program on this computer has it. See Port.

If a program connects and nothing it sends goes out, look at Activity: each packet that was not sent says why.

Last updated 11 October 2026

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