Update README.md

Author: sh123

README.md

@@ -1,7 +1,7 @@
 # Introduction
 Experimental Amateur Radio single sketch Arduino NRF24L01 2.4 GHz (13cm band) USB serial KISS TNC/modem. 
 
-Could be used with Linux AX25 tools to setup packet network or other tools such as [APRSDroid](https://aprsdroid.org) or [Codec2 Walkie-Talkie](https://github.com/sh123/codec2_talkie).
+Could be used with Linux AX25 tools to setup packet network or other tools such as [APRSDroid](https://aprsdroid.org) or [Codec2 Walkie-Talkie](https://github.com/sh123/codec2_talkie). Operates via PC USB interface, USB OTG on Android.
 
 # Dependencies
 - NRF24 library (just install via libraries): https://github.com/nRF24/RF24