Android Question B4A Library [B4X] BLE 2 - Bluetooth Low Energy : Send / Receive Data

[GiovanniPolese]

Hi to Everybody
I have an Esp32 (Heltec V3) device which communicates with BLE. Using existing Apps it works. Now my problem is to make an App which sends and receives data (Ascii strings). A sort of "Chat". After browsing posts here and trying some examples, I see that receiving data is someway explained, but not sending data. Does someone here have any hint?
Thanks in advance