TTY for deaf application/emulator in LInux

TTY devices are assistive devices for deaf and HOH (hard of hearing) people. Today these devices are obsolete because they are replaced with sms via cellphone and emails. However, government are still listing TTY phone numbers in additional to regular phone numbers and emails. Unfortunately they are not replying to emails which is very annoying. Conversation over the phone is impossible for me since I am almost deaf. Therefore the only alternative option is TTY devices which are obsolete already. 1) Are there any software applications for Linux or Windows that mimic/emulate TTY so that TTY phone call can be made through pc computer connected to internet? 2) Some cellphones (android and IOS) support TTY software emulation. Which version of software support those services? Have you any experience with this feature? I am aware that android has a feature voice to text. However, most people do not speak clearly so that translated text becomes meaningless. I prefer SMS or email however, government agencies are very lethargic and obsolete themselves which makes communication with them hard. I am located in Canada.