Due to changes in US Federal 911 laws integrated cordless phones are no longer possible as extensions of the X16 system.   XBLUE Cordless Telephone Module has been discontinued. However, telephone company lines connected to the X16 system may still be connected to a cordless phone by using an RJ11 Line splitter, similar to the one depicted below. Line splitters are available in many places including Amazon.com.

This telephone line splitter allows the telephone company line to be shared between the X16 and a standard analog cordless phone. When the cordless phone is in use, the X16 Line-In-Use feature will indicate that the cordless phone is on a call and prevent other users from barging in on the cordless phone call.