Telebraille also exists for people who are DeafBlind with the use of a TTY with a braille or regular keyboard and a refreshable braille display or LVD (Large Visual Display). A relay call of a user who is DeafBlind is directly related to a relay call of a TTY user, however, the text transmission speed is often reduced to increase the ability of the user who is DeafBlind to comprehend the moving braille on the braille TTY or large print on the LVD. Telebraille relay operators must be familiar with Braille contractions that users who are DeafBlind may use. Some TTY users with mobile disabilities may prefer to use a Telebraille, due to the smaller keyboard, regardless of a sight disability or lack thereof.