04 TETRASUPPLEMENT


dispatching control centre which manages the procedure; it may switch at any moment from ambiance listening to normal communication; communications are recorded and may be extended to other parties (allowing listen only, the dispatcher being the only authorised party for the distress procedure management). The ambiance listening feature is strictly controlled to avoid privacy issues; it is activated only during a distress process. Video is sometimes used as a separate system (without connection to TETRA) only for batch operation.


Regulation functions Audio communications for bus and tramways are managed from call back requests while some other parties (controllers) may use direct or hook method for call establishments. Alias addresses are used for bus and


tramways: the alias address uses line number and an order number on the line as its address reference; a call from dispatch station or any TETRA terminal is dialed with the alias address and the address mapping table is dynamically updated according to the associated process. Dynamic groups are extensively used with


the first part of the alias address as a dynamic group. This applies not only for bus and tramways but also for security agents, maintenance, etc. Gateways to dispatchers and to data servers


must be open and efficient to allow various other sub-systems from other manufacturers to use TETRA services; a fully documented and free of license interface is of major benefit to the user allowing full integration to other systems. In conclusion, TETRA is perfectly adapted to


French Public Transport systems and is now the standard for Urban Transportation networks.


TETRA has been in use very successfully for French and Swiss urban transport since 2002. ETELM provided the majority of these networks.


A total communications solution for TEC


The past few months have seen a major change in the Control unit of TEC, the transport operator for Liège and Verviers in Belgium. TEC is now able to communicate throughout its vast route network thanks to the ASTRID TETRA network.


ASTRID is the operator of the national TETRA radio communications, paging and dispatching network designed for the emergency and security services throughout Belgium. Founded in 1998, it boasts over 60,000 users and connects all police and fire stations, along with other rescue services. However, the work of ASTRID is not just limited to the emergency services. On a daily basis, several hundred TEC buses


pass through Place Saint-Lambert, in the heart of Liège. From his control cabin, Yves Corin is


Eurotransport Volume 9, Issue 3, 2011


responsible for coordinating driver changes, checking which vehicles are ahead or behind schedule, and ensuring follow-up action in cases of potential vehicle breakdowns. His job has proven to be considerably easier over the past few months. “I need to remain in constant contact


with the dispatchers,” explains Yves Corin. “However, when using the old communication system, we couldn’t understand each other. Not anymore though – since we’ve switched


to the ASTRID TETRA network, life has become much easier!” Just like Yves, Jean-Luc Huppen also works


in the control centre for Liège-Verviers TEC. However, while Yves monitors a precise and strategic part of the network, Jean-Luc drives between 100km and 200km every day in his car to check the current situation on numerous routes. For instance, if there are bad weather conditions – a storm, ice or snow – Jean-Luc and his colleagues will drive all the routes to ensure they are passable. Jean-Luc said: “With ASTRID, controllers and


dispatchers are now in constant contact and we use a dedicated talk group, which means that


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