Open Source - How do you get the 3-way conference button to work on an analog Polycom conference phone?

If you cannot get the conference button to work on your analog Polycom conference phone, try the following:

1. In Switchvox, go to Setup > Channel Groups

2. Modify the FXS Channel Group that the phone is assigned to

3. Go to the advanced signalling options and turn on 3 way calling.