Textphones

Textphones enable deaf people to TYPE and READ

https://www.deafax.org/news/did-you-know-in-1973-the-first-uk-telephone-call-between-two-deaf-people-was-made/

https://tap.gallaudet.edu/Text/TTYBasics.html

https://collection.sciencemuseumgroup.org.uk/objects/co34216/vistel-i-telephone-terminal-for-the-deaf-by-kegwain-ltd

https://sfdh.org.uk/topic/technology/

EDT is an option in the IYU V.18 spec.

I did a search for European Deaf Telephone (EDT) and came up with some interesting links.

https://www.discapnet.es/innovacion/productos-de-apoyo/terminales-de-texto-para-personas-con-discapacidad-auditiva

https://teksttelefon.no/static/informasjon-om-teksttelefonen.html

https://www.robkalmeijer.nl/techniek/telecom/telefonie/index.html

https://commons.wikimedia.org/wiki/Telecommunications_device_for_the_deaf?uselang=de

https://de.wikipedia.org/wiki/Schreibtelefon

https://oldcomputer.info/terminal/minicom/index.htm

https://www.wikiwand.com/en/articles/Telecommunications_device_for_the_deaf

https://deafwebsites.com/technology/telecommunications-devices-for-the-deaf/

RTTY - uses BAUDOT codes