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Interesting. You don't use TTY devices then? I wouldn't be entirely surprised if those became less prevalent as telephone services decline in popularity, but I'
by fivre 9y ago
Interesting. You don't use TTY devices then? I wouldn't be entirely surprised if those became less prevalent as telephone services decline in popularity, but I'd figured most of the deaf community used them still.
- _nalply 9y agoI don't understand this question. You mean, are AWS, the credit card institution and the customs also using TTY devices? Sorry, no. And since texting (mobile short message service) TTY slowly went out of use, at least here in Switzerland. I still own a TTY device, however I haven't used it for more than ten years. An interesting technical tidbit here: My TTY is using V.21, however with only one channel and with 110 baud. I researched the TTY with recording on a sound card and analysing the tones. Bit 0 is represented by a sinus wave of 1180Hz, 1 by 980Hz with a duration of 9.1ms each. A byte was transferred with 10 bits (total duration 91ms), 1 bit was a stop bit and the other one a parity bit (I am not sure, I forgot some details). Additionally there was a carrier tone at 1080Hz which was held for about 3 seconds after the last byte has been sent. This means it was not possible that both parties simultaneously send. We had a convention that the other party is allowed to answer when we type two asterisks. A phone relay service in Switzerland still continues to use this convention in their JavaScript application. It is a simulation of the old TTY device they sold to people. I think they had to use websockets because every letter is sent to the other party right away.