Media Center PowerKEY?
models are used in cable systems that utilize the Scientific-Atlanta PowerKEY conditional access system. The “12” in the single-room model numbers refers to “1” room with “2” tuners. For the two-room model, the “22” refers to “2” rooms with “2” tuners, and the “D” refers to the integrated DVD/CD drive (see below for details). Models with an “f” are newer versions that contain FireWire ports (see below for more details).