Serial port

The serial port on the Group Telepresence 3330 (GT Mini) is labeled COM. The serial port on the Group Telepresence 3351 is labeled COM 2.

The settings for the port are: “115200,8,N,1”.

The description given here presumes that you are connecting the room system to an RS-232 DTE (a PC for example).


PC end DTE signal names Room system end
2 RXD 3
3 TXD 2
5 GND 4
    Do not connect Pin 1

Sending requests over the serial connection

Each request consists of a JSON-formatted object, terminated by a newline. The object must contain another object called request, which is processed in exactly the same way as the content of the HTTP POST request above.

For example, to dial the number 1234 send the following:


To request the current call state, send: