In Virtual Call Centre, you can Setup a Voice Message as Introduction with Options of Pressing key Option 1, 2, 3, 4, & so on..
Then Configure phone numbers to each option number. Now when your Client calls your Virtual Number your Recorded Voice Message is broadcasted to him with Key-in Options like in EPABX, the Client when Presses Option Key our IVR Server dials outbound call to your option number and connects you with your client calling your Virtual Number. Both of you start talking. Isn't it great? You save huge cost of setup a Reception with EPABX. You are charged for all outgoing calls per 30 sec. basis.So SAVE Infrastructure, Setup & Maintenance Cost.