Cell Broadcast

[tvmercia]

discovered this by accident on my phone. does anyone know much about cell broadcast? its the system by which cells can broadcast information to all phones connected to it, its the system by which vodaphone used to display the area code which you are currently in on your handset.

i have discovered that channel 200 (on o2) tells you the area codes covered by your cell, but does anyone know of any other active channels on o2?

[Neil Jones]

Cell broadcasting is an existing, though rarely used, function of cellular networks. It originated in Paris and is a technology that, like Teletext, is available in Europe but unheard of in the U.S. Its basically a variation on SMS Text Messaging.

Cell broadcasting allows text messages to be broadcast to all mobile handsets in a given geographical area. This area can range from the area covered by a single cell to the whole network. Because cell broadcast works by targeting particular cells no knowledge of mobile telephone numbers is required, unlike bulk SMS. Also cell broadcasting places a very low load on the network, a cell broadcast to every subscriber on the network is equivalent to sending an SMS message to a single phone. Network loading problems can cause severe problems in emergency situations when network usage is likely to be very high anyway and in these circumstances SMS messages can be delayed for hours or days or even lost altogether.

The cell broadcast technology provides for 65k broadcast channels so that different types of message (severe weather, terrorist, missing child etc) could be broadcast on different channels. Not every subscriber would necessarily receive all the channels and hence all the messages. Channels can be activated from the handset or remotely by the network. Ideally certain channels would be allocated for certain message types and these would be standardised globally so that travellers would receive alerts wherever they happen to be. The channels from 0 to 999 can be switched on by the terminal user, from 999 to 65,000 can only be switched on via OTA (Over The Air Activation) but all channels can be switched off by the user.

The technology has been around for years and years but is hardly used and while it could potentially be used to mass-text all mobiles such as in the event of, for example, a nuclear attack, it would be pointless because most handsets ship with the option turned off by default.

[Nick Harvey]

Didn't know that's how they do it.

I always have it switched on on my Vodafone and I partly navigate by the results, being a boring old sod who remembers most of the area codes in the country and what location they belong to.

I love driving through the centre of Newbury, where, for a short while, as you pass their head office, your Vodafone comes up with the display "01635 Cell No 1".

You also tend to get variations on the standard area code format on a Vodafone when you're on, or close to, MOD land or sites. Around Blandford Forum (home of the Royal Signals) often produces some interesting results.

[Stuart*]

You also tend to get variations on the standard area code format on a Vodafone when you're on, or close to, MOD land or sites. Around Blandford Forum (home of the Royal Signals) often produces some interesting results.

That may be because MOD have their own telephone network with its own set of area codes. It's surprising that they would wish to broadcast them over the cell network though, although it's not particularly sensitive information to know that the area code for Devonport Naval Base is 93 75, for example.

[Pete]

having turned on "broadcast message" on my E900 nothing has happened. Google claims that Orange don't support cell broadcast at all

[Nick Harvey]

That may be because MOD have their own telephone network.

Are they still on Ptarmigan, or is that long gone and replaced now?

Used to know a guy who was on the original design team for Ptarmigan.

Google claims that Orange don't support cell broadcast at all.

Check other names for it.

It's actually called "Cell Site Display" in the Vodafone menu on my Nokia from 2000.

[Stuart*]

That may be because MOD have their own telephone network.

Are they still on Ptarmigan, or is that long gone and replaced now?
Used to know a guy who was on the original design team for Ptarmigan.

The entire network was sold to a consortium which included BT in about 1999 (for the extortionate cost of £1). I imagine it has been largely upgraded or replaced. I recall there being many changes before I left MOD in 2006.