A light source module includes a light guide element, at least one light-emitting element, and a quantum dot element. A base station can reserve a wireless channel for the wireless camera for a video transmission. The 13 MHz, 9-level digital output signal may be processed for RF transmission, for audio output to an output device, andor utilized for testing by a test fixture, for example. Each telephone has a manually operable device such as thumbwheels, which can be used to specify a unique number that forms part of the network address of the telephone and which also serves as the extension number for that telephone.