I need a hardware that has capability of converting a PSTN call comes from an extension of a PBX to SIP call and transfers the call back to another extension of the PBX. After that the hardware won't be included to the call and can accept another call.
I mean when 101 extension of PBX is called it is accepted by the hardware I need. Then hardware forwards the call to a SIP IVR. IVR asks for the extension(i.e 102 is chosen). After that SIP IVR transfers the call to the 102 over the extension 101. After the transfer succeeds, hardware can accept another call from 101 extension.
Is there a hardware for that purpose. I tested a VoIP gateway with 4 FXO. It could forward to call so SIP IVR but it couldn't tranfer the call to another extension using the same line(101). It couldn't place the call on hold. Therefore when SIP IVR transfers the call it returns busy event.
I will appreciate it if you tell me if there is a hardware for this purpose.