Patent attributes
Novel tools and techniques for implementing Transparent PSTN Failover. In some embodiments, a VoIP switch might receive a call request for connection between a calling party at a calling telephone number (“TN”) and a called party at a called TN. Based on a determination that connection via a session border controller (“SBC”) between the VoIP switch and an Internet Protocol (“IP”) gateway has been lost, the VoIP switch might route the call request to a PSTN redirect TN through the PSTN. One of the Class 5 switch of the PSTN or the IP gateway might replace the redirect TN with the called TN, based on a determination that the redirect TN represents a PSTN failover. The IP gateway may then route the call request to an IP PBX for terminating (establishing) the call connection between calling party and called party, without interception by an operator, receptionizt, or auto attendant.