#####	 ######	 ####	 [**Telecommunications device for the deaf**](https://en.wikipedia.org/wiki/Telecommunications%20device%20for%20the%20deaf): [](#sfw) --- > >A __Telecommunications Device for the Deaf__ (__TDD__) is a [teleprinter](https://en.wikipedia.org/wiki/Teleprinter), an electronic device for text communication over a [telephone](https://en.wikipedia.org/wiki/Telephone) line, that is designed for use by persons with [hearing](https://en.wikipedia.org/wiki/Hearing_impairment) or [speech difficulties](https://en.wikipedia.org/wiki/Speech_disorder). Other names for the device include __teletypewriter__ (or __TTYs__), __textphone__ (common in [Europe](https://en.wikipedia.org/wiki/Europe)), and __minicom__ ([United Kingdom](https://en.wikipedia.org/wiki/United_Kingdom)). >The typical TDD is a device about the size of a typewriter or laptop computer with a [QWERTY](https://en.wikipedia.org/wiki/QWERTY) [keyboard](https://en.wikipedia.org/wiki/Computer_keyboard) and small screen that uses [LEDs](https://en.wikipedia.org/wiki/Light-emitting_diode) or an [LCD](https://en.wikipedia.org/wiki/LCD) screen to display typed text electronically. In addition, TDDs commonly have a small spool of paper on which text is also printed — old versions of the device had only a printer and no screen. The text is transmitted live, via a telephone line, to a compatible device, i.e. one that uses a similar communication protocol. >Special telephone services have been developed to carry the TDD functionality even further. In certain countries there are systems in place so that a deaf person can communicate with a hearing person on an ordinary voice phone using a human relay operator. There are also "carry-over" services, enabling people who can hear but cannot speak ("hearing carry-over," a.k.a. "HCO"), or people who cannot hear but are able to speak ("voice carry-over," a.k.a. "VCO") to use the telephone. >==== >[**Image from article**](https://i.imgur.com/eKthZGe.jpg) [^(i)](https://commons.wikimedia.org/wiki/File:Jrb_20080809_att_tdd_2700.jpg) --- ^Interesting: [^Paul ^Taylor ^\(engineer)](https://en.wikipedia.org/wiki/Paul_Taylor_\(engineer\)) ^| [^Teleprinter](https://en.wikipedia.org/wiki/Teleprinter) ^| [^Acoustic ^coupler](https://en.wikipedia.org/wiki/Acoustic_coupler) ^| [^Robert ^Weitbrecht](https://en.wikipedia.org/wiki/Robert_Weitbrecht) ^Parent ^commenter ^can [^toggle ^NSFW](http://www.np.reddit.com/message/compose?to=autowikibot&subject=AutoWikibot NSFW toggle&message=%2Btoggle-nsfw+chx38by) ^or[](#or) [^delete](http://www.np.reddit.com/message/compose?to=autowikibot&subject=AutoWikibot Deletion&message=%2Bdelete+chx38by)^. ^Will ^also ^delete ^on ^comment ^score ^of ^-1 ^or ^less. ^| [^(FAQs)](http://www.np.reddit.com/r/autowikibot/wiki/index) ^| [^Mods](http://www.np.reddit.com/r/autowikibot/comments/1x013o/for_moderators_switches_commands_and_css/) ^| [^Magic ^Words](http://www.np.reddit.com/r/autowikibot/comments/1ux484/ask_wikibot/)