TelecomFM OneStream GFX is a universal system that can connect to an installed PBX as a call router from an existing corporate network to PSTN, VoIP and GSM, or as a stand-alone unit that replaces PBX.
Orpheum offers its iVoice (SIP trunking) and hPBX (Hosted/Virtual PBX) services exclusively to businesses in the USA and Canada. Both services start at $25 per month.