As you already know, the VoiceXML <transfer> element allows us to connect two parties together. Thus far, we've shown how the IVR platform stays up in the background while the caller and callee are connected, but what if we want to take the IVR platform out of the picture altogther? Well, it's possible. We can achieve this by using a transfer type of blind rather than bridged.
When executing a blind transfer, the IVR platform (Prophecy, in this case) will connect the two parties and then drop out of the picture altogether. This leaves both calls connected at the telephone carrier level. It should be noted that while Prophecy will not remain in the connection, it will also not monitor the outcome of the transfer.
*image courtesy of the W3C VoiceXML specification
First, let's get the financial aspects out of the way. In the context of the Prophecy hosted platform, "true" Blind transfers require that the developer deploy redundant, dedicated phone lines into the voxeo datacenters with providers that support the blind transfer functionality, and are subject to the following additional fees:
A one-time setup fee
An annual recurring fee
A per-instance connection fee
For customers who choose to deploy Prophecy software locally, the ability to support blind transfers is entirely dependent upon the telco provider being used.
Customers also have the option to perform a SIP REFER in both our hosted networks, and when doing an on-site deployment of Prophecy: Customers are required to provision dedicated SIP lines. In the context of the hosted environment, these "bring your own SIP" lines are required to be redundant, and use different carriers whose endpoints support this feature so as not to impose a single point of failure. It is strongly advised that the options of SIP REFER and blind transfers being setup be thoroughly researched with the providers in question, and that the customer proactively contacts the Voxeo team to ensure that no compatibility problems exist.
Once you're all set up, all you need to do is adjust your transfer to set "type" to either "blind" or "refer":
<transfer name="T_1" type="refer" dest="tel:+12223334444">
Please see our Prophecy Documentation for additional details specific to blind/refer transfers.
