4PSA VoipNow Express is a free, fully functional Linux IP PBX software, limited to ten phone extensions, used for hosted VoIP PBX services or in-house IP softswitch. Easy upgrade to full featured multi-tenant Professional edition.
Carousel is software to connect VoIP calls to ordinary telephone lines and vice versa using one of a number of professional telephony devices. It works as a virtual FXO gateway.
PBXpress is a voice over IP (VoIP) replacement of traditional PBX in the era of the Internet. All of your phones are connected and provisioned via an IP network, your phone calls are always recorded and connected at a fraction of the usual cost.