Speaking of news teletype sound effect

John J. Francini francini@mac.com
Thu Dec 8 00:16:47 EST 2005

At 20:25 -0500 12/7/05, rogerkirk wrote:
>SteveOrdinetz wrote:
>>Didn't those run at 56 Baud or something equally speedy?
>IIRC, it was 110 baud.

Computer teletypes -- that speak 8-bit-per-character ASCII -- ran 
(run?) at 110 baud -- 10 characters a second. Each character at that 
rate was 11 bits long: 1 start bit, 8 bits of data, and 2 stop bits.

Wire service TTYs spoke a 5-bit code, called Baudot, that ran at 50, 
60, or 75 baud. Depended on the service provider. The 5-bit code only 
allows for 32 characters. In order to handle both numbers and 
letters, two characters were reserved for the special functions SHIFT 
IN and SHIFT OUT. On receipt of SHIFT IN, the printer mechanism would 
shift from printing letters to printing figures (numbers and special 
characters). The printer would revert to letters upon receipt of the 
SHIFT OUT character.

Probably a case of Too Much Information, but I've always had a soft 
spot for TTYs...

John Francini <mailto:francini@mac.com>
| "I have come to the conclusion that one useless man is called a disgrace; |
|  that two are called a law firm; and that three or more become a Congress.|
|  And by God I have had _this_ Congress!"                                  |
|                                                       -- John Adams       |

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