***TTY/TDD Phile***
By: Captain B
For: 31337 Phreaking

Before I get into what you can do with a TTY/TDD machine, I'll go into a 
bit of detail about what it is, and It's basic use, for those who don't 
already know. A TTY/TDD is a teletype machine used by the hearing impaired 
(or deaf). It has a built in LCD or LED screen used to see what was said 
or typed by the called party, and for the calling party to see what they're 
typing (saying) to the called party. A TTY/TDD has a standard QWERTY-type 
keyboard just like on PCs and typewriters. Plus, a few special function 
keys like a Ctrl key, Esc, and whatnot. The GA (Go ahead) key is used to 
indicate you've stopped talking, and are waiting for the person on the other 
end to start talking. It must be hit at the end every time you're waiting 
on a response from the person on the other end of the line. Including with 
TTY/TDD relay operators. For a person to place a call to someone who doesn't 
own a TTY or TDD, it must be done through relay service. As the name implies, 
you dial a toll free number, wait for the TTY/TDD operator to answer, and 
ask that person to dial a number for you. In my area, it works like this: 
Local numbers are free, long distance numbers aren't. I would imagine having 
them dial a toll free number would be free, but I've never done it yet. 
Rates and what's free and not free seem to range from one area to the next. 
(Just like a lot of telecom stuff). If the person on the other end has a 
TTY or TDD, you could just dial them directly. But, you still can dial it 
through your state's TTY/TDD relay service too. To find the number for your 
state's relay service, check near the front of your local white pages. In 
my area, you can also simply dial 711 to connect to relay service. MCI and 
Sprint also offer their own TTY/TDD toll free relay service. You can sometimes 
find public TTY/TTD machines connected to payphones in select locations. 
(Usually places like train stations, bus depots, airports, and if you have 
them like I do, transportation centers). Payphone TTY/TDDs are sort of concealed 
when not in use. The TTY/TDD at payphones is contained in a steel chasis. 
The actual TTY/TDD will slide out via a motorized tray. To get it to do 
so, you must either call relay service, a TTY/TDD phone number, (local or 
long distance) or put the TTY/TDD into diagnostic check mode. Do so by lifting 
the receiver and hitting *8* *8*. (You may need to hit that combination 
of keys more than once. Some of them don't always respond the first time). 
After a few moments, you should hear a sort of click from the motorized 
tray. Then after a moment, the TTY/TDD will slide out. You'll now be in 
the statistics menu. The display will tell you to hit a number key between 
0-9. (Each being a different statistic). Reading the stats (keypress opens, 
close trys, etc.) Isn't particularly useful, though. You can also reset 
all stats to zero by hitting the 9 key. It'll say "Reset statistics? Y/N". 
Reset all stats by selecting yes(Y). Hitting the zero key will let you exit 
stats mode. It'll say "Exit statistics? Y/N". After hitting Y, you'll get 
some techno jargon "PPII Checksum=11c4" or something. After It's done displaying 
that stuff, the TTY/TDD will show the flashing display "DRAWER NOW CLOSING!". 
Keeping it open is simple enough. Any time you get that message, just hit 
any key. You can even keep it open after you've hung up the phone. But, 
it requires pressing keys a number of times until the motorized tray stops 
trying to close up the TTY/TDD. Anytime you hang up, It'll try multiple 
times to close even after lifting the handset again. Just keep hitting keys 
until It's done trying to close, and the "DRAWER NOW CLOSING!" message clears 
off the screen. If you have the TTY/TDD open while on the line, (hearing 
a dial tone) you could also dial any non TTY/TDD number. (No free calls 
unless you use an outdial, calling card or some trick of your own, though). 
Hitting any of the TTY/TDD keys while on the phone talking to someone produces 
fairly loud, high pitched tones. Some of the special TTY/TDD functions include 
holding the Ctrl key, and hitting another key. Here's a few: Ctrl+space 
bar- Announces "TTY call, please use text telephone" on the line. (Also 
displays that in text on the TTY/TDD's screen). Some announce "Hearing impaired 
caller, use TDD" instead. (Which likewise is displayed in text on the TTY/TDD's 
screen). On certain public TTY/TDDs, holding Ctrl and hitting either the 
up or down arrow keys lets you change the BAUD rate. (Although not by very 
much). Holding Ctrl+V changes over to VCO (Voice Carry Over) mode so you 
can make voice carry over calls via relay service. With this, you speak 
as you normally would to the called person, and wait for the relay operator 
to type the response. (Which, of course, you can hear the called person 
saying as their saying it through the handset anyway). I kind of forget, 
but I think holding Ctrl+ J or K skips down a line. (Only on the multi-line, 
LCD screen models. The LED screen models only have one line for text to 
be displayed). There's also something I was only able to get these public 
TTY/TDDs to do a rare few times... After the TTY/TDD opened up for the 1st 
time, I held Ctrl, then hit Q, then W, then E, then R, then T, then Y. The 
TTY/TDD repeatedly kept continuosly printing the message "The quick, brown 
fox jumped over the lazy dog" (Until a key was pressed, which stopped it). 
Now, onto how to make free calls via these public TTY/TDDs. 1st method: 
3rd party billing. As long as there's at least 1 more payphone nearby, bill 
any long distance call you want to make to the other nearby payphone. When 
asked for your name by the relay service operator, just make up a name. 
After a moment, the other payphone will ring. Pick up, you'll be told "Frank" 
(or whoever) wants to bill a call to that number. Is it okay? Obviously, 
say "yes". After that, hang up that phone and get back to the public TTY/TDD 
phone. When the person answers, the display will read something like this 
"Answered- Male voice". To make sure It's who you want, better type out 
"Is this Jim?", or whoever. After you've confirmed who's on the line, type 
responses on the TTY/TDD, and make sure to always hit the GA key when you've 
stopped talking and are waiting for a response. A 2nd method involves op-diverting. 
(Having a local, or long distance phone service company's operator dial 
the relay service number. If you can get them to). Home TTY/TDD machines 
can be bought through Radio Hack Unlimited (Radio Shack company-direct sales). 
But, even a bottom of the line model Isn't what you'd call dirt cheap. And, 
last I remember, the top of the line model sold for $599.99. The top of 
the line model has built in caller ID, stores speed dial numbers, and more. 
But, for prices like that, you could be buying a fax machine. I think most, 
if not all their models of home TTY/TDDs lets you keep printed records of 
conversations through rolls of paper tape. (Which, I think is sold seperately). 
On another phreak site once, I remember seeing a list of each state's toll 
free relay service numbers, but can't remember which. Well, I think that 
covers most everything TTY/TDD related. Have phun.