What Do I Need to Make a Maryland Relay Call? 

QUESTION: What is a TTY/TDD? What is a VCO Phone? What is CapTel™? Where can I find specialized telephone equipment?

ANSWER: The term TTY stands for Teletypewriter. TDD stands for Telecommunication Device for the Deaf. Both terms, TTY/TDD mean the same thing, however, please note that "TTY" is the most commonly used term. For information regarding where to purchase this equipment, contact us.

The TTY is a device that looks like a small typewriter with a display screen. The TTY allows a person to type text messages through the telephone line to other TTY users. TTYs are equipped with acoustic cups and/or direct connect modes. There are several TTY distributors across the country that offer a variety of TTYs with features built in.

A TTY takes a typewritten message and transforms each letter of the message into tones (beeps). These tones are called BAUDOT. Baudot is used by some TTYs to communicate at a rate of 45.5 characters per minute. Baudot TTYs are considered a "legacy" product among other TTY protocols that provide higher transmission speed.

The VCO (Voice Carry-Over) Phone looks like a standard phone and it has a display screen for reading text messages. This VCO phone allows the person with a hearing loss to "voice" their conversation directly to the called party through relay. The Operator (OPR) would then type the called party's message and it would show up on the VCO phone's display screen. This feature is called Voice Carry-Over (VCO). Some VCO phones have pre-programmed buttons. Setting up a Customer Profile is strongly encouraged with VCO users.

CapTel™ looks and works like an amplified telephone, but everything your caller says is displayed in text, word-for-word while you are listening to the speaker. It is not a TTY, but is a telephone with built-in captions, designed to let you have a more natural interactive conversation.

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