On Wed, 29 Sep 2010, Steve Terry wrote:

"Rupert Moss-Eccardt" wrote in message
...
Steve Terry wrote:

Clearly there are two distinct points of view, one that stifled
cellular PTT offers cheap and practical closed group comms for the
benefit of all users, and two those with a vested interest in
perpetrating the vast bureaucracy and ?Billion budgets of Tetra that
didn't exist ten years ago, and are looking forward to a replay with
even bigger budgets and careers to be made with the future planned
Tetra 2.

GSM can't do the sort of PTT that is required by the emergency
services. I suppose you could design something on top but it wouldn't
really be GSM anymore. One of the fundamental problems is the fact
that GSM takes a while for call set up.

I believe Orange's PTT ran over GPRS data which is left running
near enough continuously.

Skype on Three i leave running continuously whilst minimised, sometimes
for weeks on end.

Presumably, providing universal 3G coverage to the emergency services
would be an entirely different kettle of fish. Very expensive fish.

tom

--
Mpreg is short for Male Impregnation and I cannot get enough. -- D