This is a feature of CUCM CTI Transfer application. When you press the transfer button, the system automatically places the transfer leg of the call on hold while the transferring party dials the transfer-to location. Then the transferring party can press the Transfer button again (blind transfer) after dialing, or remain on the line until the answer party answers and perform a "Consult" transfer when the transfer-to line answers. In either scenario, the second press of the Transfer button, completes the transfer process and connects the transfer party to the transfer-to party.
Hope this helps.
-Sean
