Access for 9-1-1 and Telephone Emergency Services

Number of TTYs

In order to afford 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. Every call-taking position needs its own TTY equipment because experience has shown that:

With TTY or TTY-compatible equipment at each call-taking position, call takers can handle TTY calls as effectively as voice calls. Call takers at PSAPs that had only one TTY per center had significant difficulties handling TTY calls within their standard answering time. Sharing a TTY among several call takers may result in undue delay in obtaining the TTY and connecting it to the answering position. Transferring a TTY call from a non-TTY-capable answering position to a TTY-dedicated position may result in the call being disconnected or undue delay in answering the call. In some cases, transfers may result in the loss of enhanced features, such as automatic number identification and automatic location identification information. Each call taker needs to query every silent, open line call as a potential TTY call, as described in Section D, below. Because most PSAPs receive many silent, open line calls, often more than one at a time, each calltaker must have his or her own TTY equipment to be able to query all of those calls with a TTY.

Thus, PSAPs may not provide TTY equipment at only a limited number of positions, such as, at only a supervisor's position, or at only one dedicated call taker's line. PSAPs must have systems that respond to TTY calls as promptly and reliably as they respond to voice calls. Call takers cannot be required to transfer TTY calls to specific phone lines or locations, unless voice calls are also transferred under the same circumstances. Transfers consume critical time, greatly increase the risk that the call will be disconnected, and may result in the loss of enhanced features, such as automatic number identification and automatic location identification information.

People other than "dedicated" call takers often act as call takers and therefore must have their own TTY equipment. For instance, dispatchers will often take overflow emergency calls when all dedicated call takers are busy, and supervisors may take calls on occasion. Every person who takes emergency calls from the public under any circumstances must have their own TTY equipment for the same reasons that dedicated call takers must have their own TTY equipment.

Q: If a PSAP has only received a few TTY calls per month over the past year, why does it need TTYs at every call-taking position?

A: Most PSAPs receive many silent open line calls, which may be TTY calls. In order for call takers to know if silent calls are TTY calls, each call taker will need TTY equipment to query every silent call with a TTY. It is possible that call takers have been receiving more than a few TTY calls per month, but have treated them as silent lines or hang-ups rather than TTY calls. This is likely if the call takers have not been querying all silent lines with TTYs. Some of those silent lines or hang-ups may have been TTY users waiting for a TTY response.

Historically, many persons who use TTYs have not had confidence in the accessibility of 9-1-1 services and have not attempted to make direct TTY calls to their PSAP. The number of TTY calls each PSAP receives is likely to increase in the future, as PSAPs become more accessible to TTY users, and as TTY users learn of PSAPs' improved accessibility.

Q: If a PSAP complies with a State law, which requires only one TTY per PSAP, is that PSAP also in compliance with the ADA?

A: No. Satisfying State law requirements does not mean that a PSAP is also in compliance with the ADA. Some State laws require only one TTY per PSAP. The ADA, however, requires direct, equal access, which means that PSAPs must have enough TTY equipment so that each call-taking position has its own TTY capability. Also, if a PSAP has extra voice telephone equipment in case of malfunction, which most do, the ADA would also require them to have back-up TTY equipment. Therefore, under the ADA, virtually all PSAPs must have two or more TTYs.