Siemens offers their first PAT mobile phone

August 18, 2004

With the introduction of the CX 70, Siemens mobile is the first manufacturer to offer an end-to-end solution for "Push and Talk" (PaT) based on open specifications. The service features walkie-talkie functionality over mobile networks and makes group calling easier and faster than ever before. As the first Voice-over-IP application, Push and Talk is based on the IP Multimedia Subsystem (IMS), the technology platform for many future multimedia services.

"We don't want any proprietary solutions and also employ open standards for Push and Talk," Lothar Pauly, Member of the Board of Siemens' mobile communication division, explains. "Only with complete interoperability will we be able to develop the promising potential of this new service to the full." To ensure that Push and Talk works as quickly as possible across all networks and with as many devices from other phone manufacturers as well, Siemens mobile is relying on IMS switching technology, which enables IP-based connections between mobile phones and is based on the specifications of the Third Generation Partnership Project (3GPP). IMS will be the control layer for many innovative multimedia services, such as video transmission, instant messaging and virtual reality application like multiparty gaming.

For network operators, Push and Talk over IMS, which can already be implemented into GPRS networks, represents another step towards 3G. The IP Multimedia Subsystem is part of 3G mobile communication. Early integration of this technology facilitates the quick implementation of new IMS-based services. The Push and Talk server can be seamlessly integrated into the IMS network structure and linked to existing infrastructure components.

This is how Push and Talk works: First, the user selects the people he or she wants to talk to from a list. At the push of a button, all of these previously defined addressees receive an invitation which they can accept or decline. As soon as the calling partners have confirmed, the initial caller pushes the PaT button and starts the conversation, which everyone hears simultaneously. There is no time-consuming call setup, because the "Always On" feature of the GPRS network maintains the connection all along. Any group member can reply by pressing the PaT button. The communication can only go in one direction at a time, however: whoever presses the PaT button first, talks first. Push and Talk is therefore similar to traditional voice radio, although the new service can do much more. Since it runs over mobile networks, it can be used anywhere, even internationally. And PaT calls can be heard only by the registered members of a group call - a clear benefit in terms of security.

The potential of Push and Talk is huge. As operators roll out the service through all their networks, they are adding a new option which is characterized primarily by speed. According to industry analyst Northstream AB, Push and Talk has the potential to increase the traffic over mobile networks. The mobile voice chat supplements SMS and eliminates the cumbersome setup of conference calls. This mobile service will soon be able to replace the traditional radio communications of freight forwarders, courier services, taxi companies or building contractors. For private users, Push and Talk has a chance of becoming the latest trend.