The very first braille computer terminal was invented by a woodworking teacher at the Perkins School for the Blind named David Abraham. This was in 1951. It was very different from what we would now recognize as a refreshable braille display device.

The modern type of braille display was developed by the National Institute of Standards and Technology in 2000.
The National Institute of Standards and Technology invented the Braille display in 2000.

There is no connection between Braille and Sign language.

Braille is a reading system invented by Louis Braille. Braille is a tactile writing system used by people who are visually impaired. It is traditionally written with embossed paper. Braille users can read computer screens and other electronic supports thanks to refreshable braille displays. They can write braille with the original slate and stylus or type it on a braille writer, such as a portable braille notetaker or computer that prints with a braille embosser.

Sign languages are natural languages that develop among deaf communities. There are hundreds of major sign languages spoken all over the world. Signing involves the hands, arms, face and other body parts to speak, instead of speaking with the vocal cords.