The Hindu Business Line : Getting pushed to talk about push-to-talk

There is nothing inherently wrong with jargon or techno-speak. At least, as long as it doesn't invade general news; for, otherwise, we get pushed to finding out more about the new word or phrase.

Take for example, PTT that leaps from `Hutch under DoT scanner for PTT service' — a headline of Monday. Or, from `Optimi to assist LatAm operator in PTT launch,' as in a September 22 report in Cellular-News. Or, again, `Brightstar, Kodiak team up on PTT-enabled devices,' as on www.telecom.paper.nl. Time for a zero base on PTT if you don't want to be pushed further.

`Push2Talk and Push2Show,' reads a headline in Von Magazine. And the report by Bob Emmerson, European Editor, offers help. "Push-to-talk (PTT) is wireless VoIP," he begins. Wait. What is VOIP? Voice over Internet Protocol, "a technology that allows you to make telephone calls using a broadband Internet connection instead of a regular (or analogue) phone line," explains www.fcc.gov, the site of the US Federal Communications Commission.

More jargon

Brace up for more technology terms. That SIP is used in push-to-talk to establish the PTT/IP session and that it can be linked to presence and availability, as continues Emmerson. SIP, please note, means the Session Initiation Protocol, "a signalling protocol for Internet conferencing, telephony, presence, events notification and instant messaging," as defines www.cs.columbia.edu. IP or Internet Protocol is "the most important of the Internet data transfer protocols," says www.geekazoid.com. "IP enables a data packet to travel multiple networks on the way to its final destination."

PTT, "also known as `Press-to-Transmit', is a method of conversing on half-duplex communication lines, including two-way radio, using a momentary button to switch from voice reception mode to transmit mode," defines Wikipedia. A page on `duplex communication' explains the phrase as `one where signal can flow in both directions between connected parties'.

The common telephone is a simple example of such two-way traffic, but it is `full duplex'. In contrast, "a half-duplex system allows communications in both directions, but only one direction at a time (not simultaneously)." Haven't we seen policemen using such wireless systems to communicate, and saying `over' to indicate the end of transmission?

Emulating walkie-talkie

With PTT, the mobile emulates the walkie-talkie. Doesn't that seem like a climb-down, you may ask? Don't the mobiles that we use offer full-duplex communication, so why should anyone be interested in the half-duplex variety that PTT offers? Because "You can stay on line for hours," points out Emmerson. And "you're only charged for talking time!" Great for teenage daughters, but they and all their friends would need a PTT phone, he adds.

Yet, before you start pushing the buttons, it helps to know that PTT needs a different hardware. "Nextel Communications (now merged into Sprint) introduced mobile PTT several years ago using iDEN," informs http://en.wikipedia.org. The abbreviation stands for `Integrated Digital Enhanced Network' a mobile telecommunications technology, developed by Motorola, "which provides its users the benefits of a trunked radio and a cellular telephone."

Nokia calls it PoC or `Push to Talk over Cellular'. A new real-time direct one-to-one and one-to-many voice communication service in the cellular network, explains www.nokia.com. "The principle of communication behind the service is simple — just push to talk." Ah, nothing could be simpler. "Thanks to the `always-on' connection, calls can be started to both individuals and talk groups with just a push of a key. The call connection is almost instantaneous and the receiver doesn't have to answer the call," says Nokia.

Differentiated service

PTT allows service users to be `engaged in some other activity than a telephone call', even as `they listen to the group traffic during their activity.' Fast creation of `talk groups and group calls,' is possible using this `differentiated voice service'. Which explains why the Department of Telecom (DoT) recently asked Hutchison-Essar as to under what licence the company has offered its push-to-talk service.

This isn't the first time that the Government has pushed back push-to-talk. "Tata Indicom became the first mobile service provider to launch PTT in India," informs www.tata.com in a posting dated December 2004. "The PTT service will enable up to four subscribers across the country to talk to each other," wrote Jonah Ramball then on www.techtree.com.

But Tata Teleservices had to hold back when the Department slapped a Rs 50-crore penalty on the company, `for violating ISP (Internet Service Provider) licence conditions' and posing possible `threat to national security', as http://goliath.ecnext.com notes in a posting dated September 2005. The Telecom Disputes Settlement and Appellate Tribunal is reported to be currently seized of the matter.

During the days of launch euphoria, PTT-enabled mobile phones recorded a spurt in sales in cities, as news reports informed a year ago. And one also heard about how both the corporate sector and youngsters queued up to buy in big numbers! Alas, their wait may last a bit longer till the PTT disputes get resolved.

However, one may wonder if operators stand to gain when one can talk to many. "It's very profitable for operators," assures the report on www.vonmag.com by Emmerson. "The real market is emerging and will develop in line with the service and device availability."

Voice equivalent of IM

As if to affirm, a page on www.motorola.com exhorts, "Push-to-xperience new revenue opportunity." It speaks of PTT as `the voice equivalent of IM or Instant Messaging', to capture "the richness of voice conversation that is otherwise lost in text-based messages, while giving users a direct `hotline' to their buddy or group." Enticing, isn't it? "PTT represents incremental revenue to the wireless carrier, as it is an additional service that does not replace normal cellular mobile communications service, but rather is a VAS (value-added service) add-on to existing service," argues www.mobilein.com.

"Perhaps one of the greatest benefits that wireless carriers enjoy from PTT is the network cost efficiencies that are realised in at least two ways," says MobileIN.com. How so? "Use of the underlying IP-based network with half-duplex transmissions has the advantage of both requiring less bandwidth (e.g. network and facility savings) as well as avoiding interconnection to the PSTN or Public Switched Telephone Network (e.g. savings against interconnection charges)."

Push-to-talk may well turn out to be a technology that may, therefore, get a saving push in addition to demand pull!

ZeroBase@TheHindu.co.in

D. Murali

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