Hands-Free Auto Answer SIP Call Transfer
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Solution Overview
Problem
In communications systems using Session Initiation Protocol (SIP), existing technologies require users to manually answer calls after initiating a call pick-up request, violating the end-to-end media stream negotiation and offer/answer model, which increases user effort and processing overhead.
Innovation Solution
The system implements a Hands-Free Auto Answer (HFAA) mechanism that automatically transfers calls from one SIP phone to another without user interaction, using SIP Invite and Refer commands to establish a communications session between the initial caller and the call agent, allowing SIP phones to automatically go off-hook and retrieve calls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual call pick-up is implemented in SIP systems, then call transfer capability is achieved, but user effort increases and offer/answer model compliance is violated
Solution Approach 1:
The system performs preliminary actions by pre-negotiating media parameters and establishing the offer/answer model compliance before the actual call transfer occurs. The SIP phone is pre-configured with HFAA capability, and media parameters are pre-negotiated between the picking phone and the original called phone, so that when the transfer happens, no additional user action is needed and model compliance is already satisfied.
2Adaptability or versatility
If manual call pick-up is implemented in SIP systems, then call transfer capability is achieved, but processing overhead increases
Solution Approach 1:
The system implements self-service by enabling the SIP phone to automatically negotiate media parameters and complete the call transfer process without requiring user intervention. The HFAA mechanism allows the phone to autonomously handle the complex media negotiation and offer/answer model compliance, reducing the processing overhead on other system components.
3Ease of operation
If automatic call transfer is implemented, then user effort is reduced, but media stream negotiation compliance may be violated
Solution Approach 1:
The patent uses the SIP phone itself as an intermediary that mediates between the call transfer request and the media stream negotiation. The phone's HFAA mechanism acts as a mediator that automatically performs the media parameter negotiation and ensures offer/answer model compliance while maintaining end-to-end media negotiation, thus preserving reliability without requiring user effort.
Data Source
AI summary
In accordance with a non-limiting example, the system and method places a call from a first call device used by a party A to a second call device such as used by a party B by routing the call from the first call device into a communications server that establishes an internet protocol (IP) call between the communications server and the second call device. A third call device such as used by a party C monitors the second call device. A first SIP invite command is sent from the third call device to the communications server as a pick-up call instruction for the call to the second call device when it has not answered the call from the first call device. A second SIP invite command is sent between the third call device and communications server and the call is transferred from the second call device to the third call device to establish a communications session between first and third call entities.