Callers with hearing or speech impairments may use special text devices to initiate a call into a call center. These devices are called Teletype (TTY) for the hearing impairment. TTY is also called as Telephone Device for the Deaf (TDD). Traditionally, a special type of machine was needed at the receiving end to interpret this text and responses. Avaya one-X Agent, in conjunction with the Communication Manager PSTN Gateways, provides integrated TTY conversation support for an agent. These TTY interactions appear as normal My Computer telephone calls to the agent, except that Avaya one-X Agent detects the text tones and displays them for agents. Similarly, an agent can type characters and these tones are converted back to descriptor tone packets back for Communication Manager gateway to convert to the PSTN tones required.
The TTY interaction appears in a window similar to the IM window. Agents interact with TTY callers with normal roman alphabet text character text, as well as a set of standardized abbreviations available on the TTY interaction window. Messages exchanged between the caller and the agent are normal characters during a TTY session. TTY protocols rely on a significant number of abbreviations. For instance, Go Ahead (GA ) is the signal that the person currently typing has paused and is waiting for a response back from the other end. Such human protocols are needed because TTY is a half-duplex, character at a time transmission.