Written by: Niclas Medman, Krister Svanbro and Per Synnergren

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Push to talk is a quick and informal way of communicating person-to-person and with groups. With a simple push of a button, users can activate voice communication with friends and family—much the same way as using walkie-talkies or private mobile radios. But because it is a mobile communication service, push to talk also enjoys the range and wide area coverage of traditional mobile services.

Ericsson Instant Talk is a voice-over-IP (VoIP) service set up using the session initiation protocol (SIP). The technical realization is based on a total business approach that gives operators a complete solution consisting of the Instant Talk Application Server, the IP Multimedia (IPMM) system, terminal clients, and professional services. Ericsson’s practice of basing products on open standards—to ensure interoperability and rapid uptake of service—also applies to Instant Talk.

The solution is fully compliant with the push to talk over cellular (PoC) specification. It has also been built with service evolution in mind, giving operators the ability to add new features and services to enrich the service and the IPMM.

[First published in Ericsson Review no. 01, 2004]