Abstract: A method of operating a cellular base station subsystem such as a smart bias tee. The method comprising: modulating a first control data signal to generate a first modulated carrier signal; multiplexing said first modulated carrier signal with a first RF antenna signal onto a feed line; demultiplexing a second RF antenna signal and a second modulated carrier signal from said feed line; demodulating the second modulated carrier signal to generate a second control data signal; analyzing at least one of said signals to generate diagnostic data; and outputting said diagnostic data. The subsystem also has an addressable memory adapted to provide data on request from said subsystem.

Abstract: A cellular telecommunications system and methods of monitoring, control and communication within such a system. In one aspect redundancy is provided by a second mode of communication for control signals should the primary mode be unavailable. In one embodiment a secondary wireless network is provided in case of failure of a backhaul link. This allows the control of ancillary equipment in case of unavailability of the primary mode of communication. In another aspect continuity of telephony signals may be provided in a cellular communications system by utilising one or more wireless link between base stations to convey telephony signals normally conveyed via a backhaul link.