20 August 2002 -- After co-operating since 1995, Hamburg-based Pandatel is supplying Alcatel with 90 customised asynchronous FM multiplexers for its ESTW L90 railway signal boxes, providing data transmission that is both efficient and redundant for signals between the individual railway stations and the central signaling office.
The TDM technology of the modular FM multiplexer allows up to 2x24 different signals to be transmitted over one pair of optical fibres. "Especially in the area of control and safety technology, high availability is called for", says Pandatel product manager Frank Stockmann.
Hence, power supplies for both multiplexers in the 19" rack are provided redundantly. A further safety factor is the ring configuration, which permits continued communication in the event of a broken fibre cable. The add-drop procedure allows sub-stations to be optimally inserted into the data flow, for which the multiplexers must support the unusual 20mA interface.