BTReadUTF channel, data$
This command reads 16 bit unicode characters, in the UTF-8 string format, from a specified Bluetooth channel. Any data read is returned in the data$ parameter. This command should be used to receive a string sent by a BTWriteUTF.
After a BTReadUTF it is important to check if the read succeeded. All serial communication is subject to interruption at any time so check the BTGetError$(n) after each Bluetooth command you execute. BTGetError$(n) will return an empty string if the read succeeded.