Cactus implements a software-based Voice-over-IP private branch exchange.
BSEditor: Cactus implements a software-based Voice-over-IP private branch exchange (IP PBX, IPBX) on a normal Windows PC. It is compatible with all standard-compliant SIP phones and soft phones, and with all well-known SIP providers like Cox, Free, Fastweb, Neuf, Sipgate, Voipbuster, Voipgate, Voiptalk, Voipstunt, UGC and many others (not with proprietary services like Skype, though). Internal phone conversations do not cause external IP traffic, enhancing Privacy and reducing Internet load.

Using an ISDN card, VoIP/SIP can be integrated into an existing ISDN PBX so that conventional or ISDN telephones can be used for inbound and outbound VoIP conversations. Alternatively, the ISDN card can also be connected to a public switch.

Multiple Cactus PBX PCs can be connected together so that their branches can be dialled directly as if they were in the same building. The Internet telephony connection can either use a conventional DSL/cable router or the Windows RAS/PPPoE driver. Other features include:

* Allows different external escape Digits for business and private calls (0 and 9)
* Optionally intelligent automatic external access based on the length of dialled numbers
* Transfer calls to internal or external VoIP or ISDN numbers, using Hold and Transfer functions
* Short access codes and group numbers easily configurable, multiple phones can ring in parallel
* Native call diversion for busy or out-of-office, does not require diversion function in SIP telephones
* Call-Through: Transfer an inbound call to one or multiple internal and external destination numbers
* Call routing: Outbound calls can be routed to different SIP providers or ISDN depending on the area code
* Fallback to backup provider or ISDN if the Default SIP provider is not available due to a temporary outage
* Adapts itself to the habits in your country, e.g. 0 or 1 as long-distance prefix and ISDN a-Law or 碌-Law. you can free download Cactus 1.23 now.