Patent ID: 8559604

Claim:
A method comprising: submitting an extension call request to a telephony system, wherein the extension call request identifies a recipient extension; receiving a return message from the telephony system in response to the extension call request; determining whether the recipient extension is currently associated with the telephony system based on the return message received from the telephony system; documenting an association between the recipient extension and the telephony system if the recipient extension is currently associated with the telephony system; wherein the extension call request comprises a Skinny Client Control Protocol (SCCP) offhook message identifying the recipient extension; wherein the return message received from the telephony system comprises an SCCP dialtone message if the recipient extension is currently associated with the telephony system; and wherein the return message received from the telephony system comprises an SCCP dialtone denial message if the recipient extension is not currently associated with the telephony system.