Abstract: A system for distributing multimedia information from a central office to a plurality of customer's premises each interconnected to the central office with a dedicated optical fiber includes a switch for transmitting a plurality of optical bands from the central office to each of the subscriber premises. The switch, being located in the central office and controlled by selection signals provided to or by the central office, selects a subset of first signals, either electrical or optical, and blocks others of the signals that are not contained within the subset so that the customer receives only the signals subscribed to by the customer. Each customer's premises has a receiver, coupled to the corresponding dedicated fiber, to detect the subset desired by the customer.

Abstract: A telephone wire pair is qualified for digital signal transmission by central office testing. The tip-to-ring capacitance of the wire pair is measured while applying an test signal in the 20-30 Hz range to the wire pair. The tip-to-ring capacitance is used to compute a first length, and the first length is compared to a pre-determined length. If the first length exceeds the pre-determined length, then the wire pair is qualified based upon another comparison of the measured capacitance to a pre-determined capacitance. On the other hand, the first length is less than the pre-determined length, the tip-to-ring capacitance is measured at a frequency of, preferably, 600 Hz. The test signal at this frequency minimizes errors due to resistive and inductive components of the primary constants of the wire pair and/or a ringing device connected to the wire pair.