Individuals who are deaf or who have speech impairments use a TTY/TDD to make and receive telephone calls. A TTY is a piece of equipment which has a small keyboard and visual display. The person using the equipment types what they would like to say and the information is shown across the display. TTYs use a coupler or modem to convert electric TTY impulses into acoustic signals which are then transmitted to a telephone receiver. The signals are sent to the receiver's TTY and are converted into text messages. In order for a person to use a TTY/TDD, the individual at the other end of the conversation must also have a TTY/TDD or they must use a relay service. When a relay service is used, one person types his or her part of the conversation into a TTY/TDD. The message is read by a relay operator who also has a TTY/TDD. The relay operator then verbalizes the message to the other party. As the other party makes a response, the relay operator types their message into the TTY/TDD unit and the message is then read by the person who is hearing or speech impaired. In addition, TTY communications technology enables people who may be deaf or who have a speech impairment to use a computer as a TTY.