Minimalistic Android KISS Bluetooth/USB modem client for Amateur Radio DV (digital voice) communication by using open source [Codec2](https://github.com/drowe67/codec2).
This minimalistic Android application is a digital voice frontend for your radio. It connects to your radio KISS Bluetooth/USB modem, sends and receives Codec2 audio frames, which are encapsulated inside KISS frames. It does not deal with radio management, modulation, etc, it is up to your modem and radio, it could be just AFSK1200, GMSK 9600, LoRa, FSK, FreeDV or any other modulation scheme. Radio just needs to expose KISS Bluetooth interface for speech frames.
- **PTT button**, push and talk, Codec2 speech frames will be transmitted to the modem
- **USB serial connectivity** (115200 bps, 8 data bits, 1 stop bit, no parity), just select this app after connecting to USB and it will use given connection
- **Bluetooth connectivity** on startup, lists paired devices, so you can choose your modem and connect, you need to pair with your Bluetooth device first from Android Bluetooth Settings
- **Voice codec2 mode selection**, which allows you to select various codec2 modes from 450 up to 3200 bps.
- **Codec2 loopback mode**, which records and plays your recorded voice back to test and evaluate different Codec2 modes and speech quality
- most likey you do not have enough bandwidth, use higher throughput modem mode, for LoRa modems you need approximately 170% of data rate for the given codec2 bitrate
- modem goes into RX state too fast after sending first packet, increase TxTail parameter for your modem, so it will longer TX tail before switching to RX
- Modem profiles, so different modems could be controlled from the UI with KISS command extensions, so that user can change frequency, modulation scheme or other modem parameters.