San Mateo start-up Sonim Technologies will push its push-to-talk mobile phone technology in Europe and Asia, given that Nextel dominates the U.S., according to VentureWire (sub required) today:

Sonim Technologies Inc. has raised an $8.3 million third round of funding to help spread its push-to-talk technology in European and Asian markets.

New investor SIAR Capital led the round, which closed a few weeks ago, with participation from existing investors Apax Partners Inc., 3i Group PLC, Accel Partners and BV Capital.