what you mean by push to talk?

[Systran]

Hi,friends
Does anyone have an idea of Push-To-Talk option
How does it work ??in what circumstances we can avail this service

thank you..

[N I C K]

Push-to-Talk (PTT or P2T), originally introduced in the US,push to talk provides end-users with the ability to quickly find one another and engage in brief, burst-oriented style communication
At the core of PTT is an IETP standardized protocol known as Session Initiation Protocol (SIP) used for IP communications and Wireless Softswitch network infrastructure. Being that it uses IP as a transport/bearer, PTT is highly dependent on the roll-out, expansion and improvements of 2.5G and 3G technology and infrastructure.
Use of the underlying IP-based network with half-duplex transmissions has the advantage of both requiring less bandwidth .it has savings against interconnection charges...

[Simond]

There are mobile phones that have the "push to talk" feature in addition to their normal features. It's like using a walkie talkie. the only drawback with this feature is that you can only talk with people on the same network that supports feature on their phone.Not every cellphone has this feature

[Gonzo]

PTT PoC or Push to Talk over Cellular is a feature similar to walkie-talkie that is provided over a cellular phone network. A typical Push to Talk connection connects almost instantly. One significant advantage of PoC is allowing a single person to reach an active talk group at a button press, thus users no longer need to make several calls to coordinate with a group.however this service is not currently available in India...