I had been asked to create a one-button solution to dial a videoconference on a polycom group series. The unit was on a mobile cart and did not have a fixed IP.
I used the Polycom Intergrator Manual to get the API command needed:
dial addressbook name
Where name is the unique first name of an entry in the address book. I needed to create a serial connection from the button to the polycom serial cable (part number 2457-63542-001) . I first tried an arduino with a MAX3232C transceiver and DB9 connector, but it could not send the signal required. I switched to a raspberry pi instead and a FTDI usb to serial adapter which worked correctly.