tty 911 for cool kids of 911 training

TTY / TDD Machines What They Are – How They Work What YOU Need to Know

Mark J. Fletcher, ENP Chief Architect Avaya Public Safety Solutions

© 2012 Avaya Inc. All rights reserved. 2

What is TTY / TDD?

!  A TTY, whis is also known as a Teletypewriter Device for the Deaf (TDD) is a special text terminal that allows individuals who are deaf, hard of hearing, or speech-impaired use a standard telephone device to communicate with others.


!  Some 9-1-1 calls will arrive through a Relay Service as standard voice . . .

TTY/TDD Relay (711)

Voice*

Voice / TDD Relay

711 Call Via TDD

*Remember: NO ANI/ALI since the call is via the Relay Center and NOT the originating caller Call may come in on Admin lines


!  Other callers may arrive directly to your center and require you to interact via a TDD/TTY device.

911 Call Via TDD

911 Call Via TDD*

*ANI/ALI delivered since the call is direct to 911 from the line of the caller


TTY/TDD Facts You Should Know

!  Half duplex –  Like radio, 1 side can speak at a time




GA – GO AHEAD




!  No error correction –  What you get, is what you get





!  No “handshake” –  Ready or not, here I come!






!  No carrier tone –  RU There?






!  No carrier tone –  RU There?

!  No ability to interrupt –  Hold on!


HELP! I am only getting symbols and numbers!

!  Baudot is formated very specifically.

!  Each character consists of seven tones:

!  A start bit at 1800Hz

!  5 tones at 1400 or 1800Hz

!  A stop bit at 1400Hz


Got Garbage? HIT THE BAR! – The SPACE Bar

!  The same sequence of tones will mean letters when in “letters” mode

!  or a digit or punctuation mark when in “figures” mode

!  The Space Bar will often change modes

!  For example:

!  The sequence 00001 means either the letter E or the digit 3

!  If the TTYs get out of mode synchronization, then you will see numbers and digits on your TTY when you should be receiving text, tap the Space bar on your TTY to get it to resync.

© 2012 Avaya Inc. All rights reserved. 13 13

Knowing you are getting a TTY Call - LISTEN

!  How do you know you are getting a TTY Call?

!  Some devices will ‘announce themselves’ with a recorded message

!  “This is a TTD or TTY call”

!  In other cases you will hear the user pressing keys or the Space Bar to generate Baudot tones

© 2012 Avaya Inc. All rights reserved. 14 14

Why to we go through the trouble?

!  9-1-1 is not easily contacted by individuals who are deaf, hard of hearing, or speech-impaired.

!  Text to 9-1-1 and Next Generation 9-1-1 will help bridge this gap, but right now, a TDD TTY may be their only lifeline in a dire situation.

!  Training, Awareness and Practice will keep you proficient at this technology, and if it saves a single life in a single center, it was worth the effort.

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