Packet radio with Baofeng UV-5R with PTT control

It’s taken me a while to get this working but here is a collection of what I did to get packet working.

For those that don’t know, packet is a form of digital radio communication based on x.25 called ax.25 meaning amateur x.25. It sounds just like your modem back in the AOL days.

Hooking up a sound modem to a baofeng uv5R is difficult. The PTT ground will close when you plug the speaker and mic into a laptop. Some people switch to VOX which may work well on APRS but not packet.


A sound Modem. PC based is easiest. I used SoundModem from

A terminal. PC based is easiest. I use AGWterminal from

Once you have the software installed, you’ll need to build or purchase some items.

Easy Digi is the cheapest and easiest way to solve the PTT ground problem. This is needed for APRS and Packet with a PC. You can find easy digi for $8 on ebay –

It comes with instructions on how to build the board.

Follow this diagram for wiring.

Once it’s built you’ll need to use 3.5mm and 2.5mm headphone wires for your PC and your HT. Ebay is a great place for these. Pickup a serial to USB adapter as well.

Some issues I’ve started to notice is the PTT will hang for a bit. Also be aware that if the PTT is on any windows sounds will go through to the packet net. It’s easiest to mute those sounds while doing packet.