Systems and methods for handling calls in a wireless enabled PBX system using mobile switching protocols

A method of routing an incoming call to a mobile telephone received at a wireless enabled private branch exchange, comprising:

• issuing a location request query to an element of a public wireless communications network to which the mobile telephone is subscribed;
• receiving a location request response from the element indicative of a status of the mobile telephone on the public wireless communications network,
• and forwarding the incoming call to a voicemail mailbox associated with the mobile telephone if the location request response indicates that the mobile telephone is not available to receive a call on the public wireless communications network;
• and sending a provisioning request before a the incoming call is transferred to the public wireless communications network, establishing a secondary call handling protocol for the mobile telephone if the location request response indicates that the mobile telephone is available to receive the call on the public wireless communications network the secondary call handling protocol defining a call handling protocol for handling calls to the mobile telephone in response to one of busy and no answer condition of the mobile telephone.

An apparatus comprising a wireless enabled private branch exchange telephone calls to terminals in a private communications system including mobile telephone for issuing a location request query to an element of a public wireless communications network to which the mobile telephone is subscribed and for receiving a location request response from the element indicative of a status of the mobile telephone on the public wireless communications network, and for forwarding, upon receipt of the location request response, to forward a call directed to the mobile telephone to a voicemail mailbox in the private branch exchange associated with the mobile telephone if the location request response indicating that the mobile telephone is not available to receive a call on the public wireless communications network

• wherein the private branch exchange is sends a provisioning request establishing a secondary call handling protocol for the mobile telephone to the element of the public wireless communications network before transferring the call directed to the mobile telephone to the public wireless communications network the secondary call handling protocol defining a call handling protocol for handling calls to the mobile telephone in response to one of a busy and no answer condition of the mobile telephone in response to the location request response indicates that the mobile telephone is available to receive the call on the public wireless communications network.