Customer premise equipment interface

Abstract

A CPE such as an ISDN telephone subset or multimedia equipment includes an interface recognition unit that connects to the network interface and adapts itself to allow the CPE to be used with standard ISDN interfaces and an analog interface. The interface recognition unit includes an interface recognition switch (IRS) that performs two functions. First, the IRS protects the CPE from damage in those instances where a non-standard network interface is connected to the CPE. Second, for standard interfaces, it identifies the type of network interface and routes the incoming signals appropriately. Specifically, if the IRS detects a T interface, the incoming signals are switched directly to a T interface circuit for controlling and powering the higher functions of the CPE. If the IRS detects a U interface, incoming signals are automatically switched to a U interface circuit for controlling and powering the CPE. Alternatively, an interface adapter is provided that delivers the signals to circuitry relating to one of the standard interfaces and monitors the CPE to determine if it is operable. If the CPE is operable, the connection is maintained. If it is not operable, the interface adapter reroutes the signals to circuitry relating to a second one of the standard interfaces. The CPE is again monitored to determine if it is operable. If it is operable, the connection is maintained. If it is not operable the connection is blocked. The IRS and interface adapter can also detect if the network interface is an analog line and route the analog signals to an analog circuit provided in the ISDN CPE such that the ISDN CPE can function as an analog telephone.