Now blogging at diego's weblog. See you over there!

In a comment to my previous post on recent moves by Nextel Juan Cruz corrected me regarding the workings of the Nextel system. He said:

Diego, in Nextel's PTT system, the message is compressed, assembled as a series of packets, and then sent to the (cell) network, that routes it to the proper handheld.

The trick here is that (from the cost perspective) is that when you send a message it usually uses the network for a couple of seconds only, and because the message goes one way, there is no need to ACK that the final recipient got it, the terminal must only make sure that the local cell has it.

Is basically a store-and-forward system.

In Argentina it (and several other countries as well) it's already a cell phone operator. The only country where it does not have decent a market as a cell-phone op is in the US.

The company is split in two branches (in the US): Nextel and Nextel International. The former handles local business and the latter only international branches.

And Jim Added:

Juan Cruz is spot on, I really didn't grasp the idea of PTT at first, but if you think of it as a form of VOIP which seems to be what FasTxt are doing with their app on Symbian phones and using GSM/GPRS as the carrier, you can see some of the advantages.

This way you only have GPRS costs for the data your phone sends and receives rather than full minute by minute pricing for a long call.

Thanks for the clarification! Obviously I got carried away by my own ideas about how these things should work :) Interesting to know that what I'm talking about (direct phone-to-phone connections when possible, something akin to WiFi in Ad Hoc mode between two nodes) doesn't even exist (at least not for cell phones :)).

Categories: technology
Posted by diego on May 23 2003 at 5:29 PM