The Interquartz Door Entry four button phone is compatible with the Avaya IP Office and will require an analogue extension of the system. A system that will allow any internal extension users to answer and allow door entry ( please note that an elctronic lock is required with this set up)
In addition to this you will require a doorphone power supply.
IP Direct can install this on your behalf so call today for an all inclusive installation Quote 0800 2802280