Background: The Americans with Disabilities Act (ADA) requires equal access to TTY users, every call-taking position within a PSAP must have its own TTY or TTY-compatible equipment. PSAPs must have systems that  enable call takers to handle TTY calls as properly, promptly, and reliably as voice calls.

Maintenance and Back-Up Requirement: The ADA regulation contains a specific provision requiring that covered entities maintain their accessibility features and equipment in operable working condition. In addition to this specific maintenance requirement, the ADA's equal access requirement obligates PSAPs to implement equally effective procedures for maintenance and back-up capability for TTY equipment as they provide for voice telephone equipment. For example:

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•TTY-PASS Program: TelecomXchange International has developed an assessment process that, once subscribed to, will allow PSAPs to test individual TTY devices to the Industry specification for TTY 9-1-1 calls originated from landline phones and wireless mobiles.  The TIA/EIA IS-840-A standard used in this assessment is the minimum performance Standard for Text Telephone signal detector and regenerator. It contains strings of random baudot characters (2000) with the nominal, minimum, and maximum values for various components of the FSK EIA/TIA 825 standard. To meet standard requirements, a TTY must complete this test with a total character error rate (TCER) of 1% or less.

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•Annual subscriptions start with the day of registration and with the PSAPs agreement to pay an annual fee (monthly installments may be an option) to run numerous performance tests and submit results for scoring purposes (PSAPs requiring manual grading will be charged extra). For questions regarding scoring please see our "Frequently Asked Questions / Help Desk" section.