Mobile software developer Esmertec has launched u@POC, a push-to-talk-over-cellular (PoC) client for 2.5G and 3G mobile devices. It lets individuals or groups talk simultaneously through a walkie-talkie style application, enables text and instant messaging communications and is compliant with the Open Mobile Alliance PoC specification, which mandates interoperability between devices regardless of network air interface standard, the user’s network or the user’s location. The client lets users create talk groups, organize talk groups and identifies participant availability.