mobile signal!

[Lore]

Whilst in Paris last week we noticed that our mobiles had full signal in the underground... does anyone know how that works?

[Buenchico]

The Metro has cables running along the tunnel walls which are linked to the mobile phone system. A similar system is being installed on the London Underground. These systems are primarily to ensure that transport staff can use their mobile phones to have instant access to their control system (and the emergency services) in the case of an emergency. For this reason, only one mobile phone company's system will be available on each underground rail system. (e.g. if all London Underground staff are issued with company mobiles connected to say, Vodafone, then Vodafone will be only system which will be accessible to Tube travellers because only their signals will be conveyed by cable).

Chris

[Lore]

Thank you Chris :o)

[the>one]

clever clogs....

[kwikfit]

If you happen to travel on the Heathrow Express through the long rail tunnel at one end, and make a call on any of the 4 main networks you'll utilise the tunnel's shared GSM system; in theory it could work on the Underground too- but the Underground has other priorities and enough trouble dealing with those!

Shared systems (known as DAS, distributed antenna systems) are very common now, similar indoor systems exist in shopping centres, like Bluewater and the Glades in Bromley- service providers like T-Mobile / O2 etc lease usage of them from companies like NTL who in turn run the service for the landlord (for example)

The other consideration re: having mobiles on the Underground is the background noise! In Paris 1 or 2 lines run on rubber tyres, so a bit less noise....