Chirp

The go-to tool for configuring your radio from the PC.

Don't use the Chirp from your standard Linux distro, it's likely to be some 3 year old version.  Install from another ppa.

TRRS connection on Android phones and Lenovo Thinkpad L580

1. TIP : left audio (30 to 40ohm to ground)
2. RING1 : right audio (30 to 40ohm to ground)
3. RING2 : ground
4. SLEEVE : microphone
   1. sometimes there's a switch to ground in parallel with the mic.
   2. In case of a Samsung headset, there's a "100ohm resistor in series with a switch to gnd" connected to this pin.

Aprsdroid

• Ham Radio Crash Course APRSDroid walkthrough
• Mobilink TNC cables

Reference

• Baofeng UV5R TRRS Adapter
• Baofeng-RPi interface