Question about Jabra Pro 920

Hello Helli_87
I can't answer your question exactly, as we had a different telephone (Alcatel system).
Basically, it should work if the telephone is connected via a LAN line.
Then the telephone output cable (handset) is plugged into Jabra and the telephone handset cable is plugged into the Jabra. In addition, you have to make a setting on the phone with headphones on/off. Otherwise it does not work.
This was the case with our telephone system. AVAYA will probably have a different function.