Abstract: In one embodiment, a method can include: (i) routing a primary call from a transferor to a transferee; (ii) routing a consultation call from the transferor to a transfer target; and (iii) forwarding a sequence of session initiation protocol (SIP) messages to a third-party device for SIP media renegotiation for transferring between the transfer target and the transferee.

Abstract: In one embodiment, a method includes sending a call invite message to initiate a call with one or more callee devices. In one example, the call invite message may be a session initiation protocol (SIP) INVITE message. The invite message may be sent to a multi-line system that is shared between multiple callee devices (e.g., a key system). A calling identifier (ID) may then be received by a callee device after sending the call invite message. The calling ID is then sent in an update message to the one or more callee devices. For example, the update message may be a SIP UPDATE message. The callee devices can then use the calling identifier to perform an action, such as displaying the calling ID for a callee to view. Accordingly, a method for providing a calling ID to a callee device is provided when a call invite message has already been sent.

Abstract: In one embodiment, a method can include: when performing a park operation: (i) receiving a first message from a park call phone; (ii) providing a second message having a park code to the park call phone; and (iii) receiving a third message having call information from the park call phone; and when performing a retrieve operation: (iv) receiving a fourth message having the park code from a retrieve call phone; (v) providing a fifth message having the call information to the retrieve call phone; (vi) forwarding a sixth message having the park code from the retrieve call phone to a parked device; (vii) forwarding a seventh message from the parked device to the retrieve call phone; and (viii) receiving an eighth message having the park code from the retrieve call phone.