In message , at 10:20:28 on Thu, 5 Apr
2012, Graeme Wall remarked:
Emirates aeroplanes are now equipped on certain routes with equipment
that allows in-flight mobile phone service.

BA have had built in mobile phones on some routes for several years
now.

There's a possibility for confusion between planes with seat-back (or
other) "built-in" phones which you can use, and being able to operate
your own mobile phone from within the plane.

Being pedantic they are both mobile phone services.

That's why I wanted to clarify the difference between the two cases, to
avoid confusion.

One is a phone service that's mobile because planes move around,

AIUI it uses mobile phone technology where available, I assume it uses
sat-phone technology when out over the Atlantic.

I think you'll find it's satellite everywhere. Apart from anything else
it's prohibited (in USA for example) to make cellular calls from an
aircraft, and the transnational billing issues would be a nightmare.

the other allows use of a subscriber's regular GSM (mobile) phone.

Which uses exactly the same technology as the built-in phones. The
difference being that the planes' on-board systems (non-phone) have
been proved to be immune from interference by random models of domestic
mobile phones.

The plane has a picocell - the mobiles used by customers don't contact
base stations on the ground. The lack of interference with the plane's
systems is largely a result of the low transmits powers needed over such
a short distance. The backhaul is then by satellite, although I think
one day there may some experimentation with "shortwave" links to
dedicated base stations.

As an aside Varig allowed mobile phone use except during take off and
landing some years ago.

That would be a third and completely different scenario (and one I can
see little evidence of, although if it was likely to be acceptable
anywhere, Brazil is the kind of place to look).
--
Roland Perry