VoIP Gateway Selection for TTY Protocol Translation
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Solution Overview
Problem
VoIP networks face challenges in accurately transmitting TTY signals due to audio compression and packet loss, requiring gateways to translate between analog TTY signals and non-audio data packets, which is economically impractical given the complexity and cost of supporting multiple incompatible TTY protocols.
Innovation Solution
A method and apparatus that route telecommunication calls based on media type by detecting the need for special media types and selecting appropriate gateways capable of providing those media types, using feature access codes or proprietary headers within SIP messages to ensure proper protocol translation and communication between IP and circuit-switched networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If all VoIP/CSTN gateway ports are configured to translate between T.140/RFC-4103 packets and traditional analog TTY signals, then TTY users can interact directly regardless of network type, but the complexity and cost of supporting all nine TTY protocols becomes economically impractical
Solution Approach 1:
The gateway population is segmented into general-purpose gateways and special-purpose TTY gateways. General-purpose gateways handle standard VoIP traffic without TTY translation capabilities, while special-purpose gateways are dedicated to TTY protocol translation. This segmentation allows the system to support TTY communication without requiring all gateways to have full TTY translation capabilities, thereby reducing overall system complexity while maintaining adaptability.
Solution Approach 2:
A proxy entity is introduced as an intermediary between the caller and the gateway. The proxy detects TTY-related feature access codes in SIP messages and intelligently routes calls to appropriate special-purpose TTY gateways. This intermediary layer enables the system to maintain simplicity in general gateways while providing specialized TTY translation services only where needed, resolving the contradiction between versatility and complexity.
2Adaptability or versatility
If traditional analog TTY signals are transported on VoIP networks using standard voice transmission mechanisms, then network infrastructure can be unified, but audio compression and packet loss cause devastating impact on TTY transmission accuracy
Solution Approach 1:
The system changes the transmission parameters by detecting TTY communication requirements through feature access codes and converting the transmission mode from standard compressed voice to specialized TTY protocol translation. Special-purpose gateways translate TTY signals into appropriate formats for VoIP networks, changing the transmission parameters to ensure reliability while maintaining network compatibility.
3Ease of manufacture
If TTY conversations are routed through special-purpose gateways instead of all gateways, then the economic burden is reduced, but additional routing complexity is introduced
Solution Approach 1:
A proxy entity serves as an intermediary that manages the routing complexity centrally. The proxy intercepts SIP messages, detects TTY-related feature access codes, and routes calls to appropriate special-purpose gateways. This centralizes the routing intelligence in a single component rather than distributing complexity across all gateways, reducing overall system complexity while enabling cost-effective deployment of specialized TTY gateways only where needed.
Data Source
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AI summary
A method and processor - readable medium for routing telecommunication calls in a communication system based on media type by detecting (602) a requirement for a special media type for a telecommunication call; and selecting (603) a subset of a plurality of gateways wherein only the subset of gateways is capable of providing communication for the special media type.