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Official Description

TerminalBT3 will connect to any Bluetooth Serial Port Profile interfaced devices such as Barcode reader, RFID reader, PC Terminal, phone to phone using TerminalBT or TerminalBT2, Arduino, Netduino, etc...

Data collected can be optionally saved in the phone as a text log and or pushed to a personal cloud. (Bluetooth-WIFI bridge)

No internet connection is necessary to collect the data unless the server/cloud option is used.
If the server option is used, and the internet connection is lost the data are buffered and sent automatically when the internet connection is resumed.

A good way to interface an IoT device interfaced with the Bluetooth SPP profile.

The ASCII data transferred form the Device are displayed to the smart phone screen.
The line of ASCII data will be displayed to the screen only after a CR/LF or CR (Carriage return / Linefeed or Carriage return) is received from the Device.

More info can be found at https://sites.google.com/site/terminalbt3/