Re:why PTT without dedicated circuit? (Score 1)

Keeping the connection open would be almost the same thing as a phone call. Looking at PTT from a social perspective, is supposed to be quick messages being sent rather than an entire conversation. In a full conversation, you may greet the person, ask how they're doing, what they're doing, etc. For PTT, if you have a simple question to ask or a message to give, you just give it, without the formalities of a phone call.

This is close to true, but there are many years of research on lightweight audio communication suggesting that open connections can actually lead to behaviors very like push-to-talk (short bursts of talk) - at least, if you are connecting people who want to be connected. After a while, the open connection is no longer considered as much of a "social contract" to pay attention (compared to the phone), and the formalities still go away.

For some recent social research on young adult use of Nextels, see http://www.parc.com/audiospaces/ptt.htm.

It'll be interesting to see how well some of the non-iDEN providers do with this. Having to wait several seconds for the receiving phone to wake up and poll the network for incoming connections seems sort of crippling for PTT.