As a user of digital radio transmission methods, you need a reliable and versatile interface between your radio device and your computer.
The LiNK500 is what you call a true plug-and-play device. It combines a high-quality sound card, CAT control, GPS, and a TNC in a compact housing. With just one USB-C cable, you connect it to your computer, and it provides you with a sound card for audio and three virtual ports for CAT, GPS, and the TNC. The device is compatible with almost any computer and operating system, as well as with tablets and smartphones. A special highlight is the TNC’s Bluetooth connectivity. However, there is an important note: due to Apple-specific limitations, CAT, GPS, and TNC unfortunately cannot be used with iOS and iPadOS via USB-C, only the sound card. The TNC connection works flawlessly via Bluetooth. Android users, on the other hand, can use all functions without any problems via USB-C and Bluetooth.
A lot of technology is required to make everything work. A TNC, a special Bluetooth module that also supports iOS and iPadOS, a sound card, a GPS, and various interfaces with the appropriate connections and power options.
There is an additional USB-A port on the front panel, ideal for connecting modern transceivers that also have a USB port, such as the Icom IC-705. The four LEDs keep you informed of the operating status at all times.
The back of the LiNK500 is just as well thought out. Here, you’ll find the power input for a voltage supply of 8-18 volts, which is especially important for standalone operation. When the device is connected to a computer, it is conveniently powered via the USB-C port. Simultaneous use of both power sources is possible without any issues. For older transceivers that do not have a USB interface, Mini-DIN jacks are available. The protocols can be set internally via jumpers on a special CAT jack – in this case, to RS232 for the Elecraft KX2. Another DATA jack is used for audio transmission and PTT control. Additional jack connections for AF-In and AF-Out offer even more flexibility.
The antenna connection is for the external GPS antenna, which is indispensable for the device’s GPS functions. This is particularly practical if you use the LiNK500 as a standalone tracker in your car and want to mount the antenna outside on the vehicle. Another advantage of the built-in GPS is the ability to use the GPS data for time synchronization of the computer via the virtual GPS USB port.
Using the sound card is child’s play. For example, if you operate FT8 with the FT8CN software on your Android smartphone, the LiNK500 is simply connected via a standard USB-C cable for power and data. If it doesn’t work, try another cable. An OTG cable is usually not required. The sound card and the three virtual USB ports are immediately recognized. You just select the port for CAT control, and you already have audio and transceiver control available in the software. As mentioned earlier, the functionality is more limited with iOS and iPadOS: here, the sound card is recognized, but the frequency has to be set manually and your transceiver need VOX for PTT.
The LiNK500’s TNC makes Packet Radio a breeze – whether via USB-C or Bluetooth. The special feature is the support for Robust Packet Radio (RPR), a protocol originally developed by SCS. This function enables secure data connections on shortwave and precise APRS tracking to receive and send positions worldwide. One detail to be aware of: the LiNK500 TNC is not in KISS mode by default. To set it to this mode, you can use the INIT string %0D%1B%40K in your software. Alternatively, you can use a terminal program like PuTTY to make the settings directly on the TNC. If you primarily use iOS or iPadOS, it makes sense to set the TNC to KISS mode by default, as there are no functional terminal programs for it and available software often does not offer an INIT option. For Windows users, there are special Init and Exit scripts available on the manufacturer’s website.
Oliver and I share a passion for plug-and-play and tidy, clean station setups. That’s also why I’ve always enjoyed building GO-Boxes, as described in my other blog posts. However, for my frequent travels and hotel stays, my desire for the most compact and minimal setup has always been very strong.
I am very satisfied to have now achieved this goal with my Minimal QRP Station 2025 Setup. It consists of the LiNK500, an Android smartphone, the KX2 transceiver with an internal antenna tuner, a wire dipole, a 3.0 Ah LiFePO4 battery, and USB and power cables. For VHF/UHF, I also use a YAESU FT-70D and a MobilinkD TNC (for voice communication and parallel APRS). The entire setup fits into a small camera bag (CULLANN MALAGA Vario 400) with internal dimensions of 9.5 x 15 x 13.5 cm and weighs only 1.9 kg, including all devices.
The LiNK500 is a masterpiece of functionality and compactness. For radio amateurs who value a simple, reliable, and mobile solution, it is a clear recommendation. This is my personal experience and opinion. I have no advertising partnership with Oliver and purchased the device at full price.
YAAC APRS Software for Linux works very well with the LiNK500. Here is a map that/which shows some Robust-Packet-Radio stations from September 20, 2025.
Here is the setup for YAAC. Important: To switch the LiNK500 into KISS mode and exit it when you close the program, use the special INIT-String: \e\w@k\r. The codes mean: E is for Escape, w@k is wait and switch to KISS, and r is return. For other software, you need other INIT strings. Please use WIDE 1-1 for RPR APRS.
The LiNK500 offers 3 virtual ports, which are recognized differently by the operating system depending on the computer. Under Linux you can query the ports in the terminal with the ls command (see picture). In my case, USB0 is the GPS, USB1 CAT and ACM0 is the TNC. This can vary from device to device and, if other USB devices are connected, sometimes change. The TNC port usually remains the same. CAT and GPS can also be swapped. Just try it out.
Note: If the USB port isn’t working on Linux, you might not have the necessary permissions. Open the Terminal and type „groups“. If “dialout” doesn’t appear in the list, you need to add your Linux user to that group. Use the following command in the Terminal to do this. Remember to replace your_username with your actual username: „sudo usermod -a -G dialout your_username“. After running this command, you’ll usually need to log out and log back in for the changes to take effect. This is a common requirement when setting up radio hardware like the LiNK500 with Linux and the YAAC software.
More about all other in my previous blog post about the predecessor model, the Teensy TNC, you will find everything you need to know about using the TNC and Robust Packet Radio: Robust Packet Radio with Teensy RPR TNC (SCS)
You can find more information and ordering options on Oliver DL4KA’s homepage: https://diy599.net
You can also find more exciting videos on the topic on Julian OH8STN’s YouTube channel: https://youtube.com/@oh8stn
If you have any questions, feel free to email me at info@dl1gkk.com.
I hope you like this article. 73 and all the best. Karl-Heinz DL1GKK