diff --git a/Digital-voice-DV-over-LoRa.md b/Digital-voice-DV-over-LoRa.md index eeed0ca..be677fc 100644 --- a/Digital-voice-DV-over-LoRa.md +++ b/Digital-voice-DV-over-LoRa.md @@ -1,3 +1,5 @@ +![alt text](https://raw.githubusercontent.com/sh123/esp32_loraprs/master/images/talkie.png) + - This modem could be used in conjunction with [Android Codec2 Walkie-Talkie](https://github.com/sh123/codec2_talkie), when application connects to the modem, instead of sending AX25 APRS packets it sends Codec2 speech encoded frames. This enables digital voice communicaiton between one or multiple modems. - Select appropriate lora spread factor `cfg.LoraSf` and bandwidth `cfg.LoraBw` depending on Codec2 speech rate from 450-3200 bps. For example, if you are using 450 bps mode and 20 kHz bandwidth then set spreading factor to 6 or 7. See data rate table above. - When using modem for voice communication `Loraprs::Service::CfgCsmaPersistence` must be set to maximum 255 value to disable CSMA, otherwise real time voice communication won't be guaranteed. Android codec2_talkie application automatically sets this parameter to 255 by using KISS P command code.