PSU-101 Power Supply for the IMF-3. (Does not power the Partylines attached to CCI-22 modules. These require Encore Master Station PSUs such as the PK-7, PS-702 or MS-702). The PSU-101 is the power supply for the IMF-3 interface frame. It has both an audible failure alarm and failure relay contacts to activate a remote signal. A single PSU-101 will power a minimum of two interface frames, depending on the type of interfaces and their individual power requirements.