We have been installing phone systems for the last 15 years and mostly Nortel, Avaya and NEC. Within the last year we started selling Grandstream and Polycom and providing Sip Trunks. We have a customer that we have had for around 12 years and we are looking to add Sip trunks to there current BCM 450 but I have never installed SIP trunks into a BCM. I am wanting to know how difficult it is and where would I go to do some research on the install process?