EWG:Draft Oct 26 Real-Time Text Reliability and Interoperability

5-B - Real-Time Text Reliability and Interoperability

This page is the text proposed in the Nov Plenary Meeting.

Go to the Oct 26 Draft of this Provision

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Proposed text as drafted in the November plenary:
If hardware or software provides real-time voice conversation functionality it must provide at least one means of real-time text communication where the following reliability requirements are met:

1. Products must use a real-time text (RTT) system that meets the following requirements:
   • RTT format must be a standard real-time text format for the voice platform that is supported by all terminal, router, gateway and other products on that platform;
   • RTT format must transmit characters with less than 1 second delay from entry;
   • RTT system must transmit text with less than 1% Total Character Error Rate at the peak network traffic specified for intelligible speech transmission (text must work on the network as long as speech does);
   • The RTT system, together with the audio system, must support speech and text in both directions in the same call session (and support speech and text simultaneously in both directions in the same call session if IP based)
   • RTT system must not utilize audio tones for transmission of real-time text over IP. Note: this is subject to a waiver of the TTY support requirement from the FCC for systems that implement IP based RTT. Also subject to consumer acceptance of prefixes or phone numbers to direct TTY traffic to gateways capable of handling TTY translation.
2. Where products or systems interoperate outside of their closed systems, they must:
   • If product interfaces with PSTN, it must use TIA 825A Baudot where it interfaces to the PSTN.
   • If product interfaces with other VoIP products or systems (outside of a self-contained product-system) using SIP it must support transmission of text as per XXX where it interfaces with other VoIP products or systems. Note: this is subject to a waiver of the TTY support requirement from the FCC for systems that implement IP based RTT. Also subject to consumer acceptance of prefixes or phone numbers to direct TTY traffic to gateways capable of handling TTY translation.
   • If product connects to other products or systems using a protocol other than SIP it must use the standard real-time text protocol that meets provision 1 above that has been established for that protocol.

NOTE: RFC-4103, TIA 1001, and MSRP (RFC4975) are being explored to fill the role of XXX. The intention is that XXX will be replaced by one interconnection format in all places it was used.
NOTE: All products may support and use other protocols in addition to these as long as they meet the 5 requirements of 5-B(1) above.
NOTE: A self-contained SIP system that uses the same real-time text protocol can be treated as a single product and can use any protocol internally as long as it supports XXX where the system-product connects to other systems or products.