Re: [RTTY] REAL TTY PICS and SOUNDS and MPGS

[Kok Chen <chen@mac.com>]

On Oct 23, 2004, at 5:43 AM, Shelby Summerville wrote:
> With all due respect, and my memories of "green keys, etc", aren't
> associated with RTTY, but our means of transmitting necessary data, 
> between
> cities, when I first started in the airline industry (1964)!

I'll bet you were already using 7 level code rather than 5 level code, 
Shelby.

My first experience with these guys was with computer input back in 
1965.  The computer was a Royal Precision Company RPC-4000.  The 
company changed names a couple of times (General Precision was one, if 
I recall) and then went bankrupt.

The input/output device for said machine was a Frieden Flexowriter.  
The tape perforator is on the side of the keyboard, so I guess you can 
classify it as an ASR.  Otherwise it just looks like a large electrical 
typewriter that vibrated like crazy when in action.  This Flexowriter 
read and punched 7 level tape (ASCII) rather than 5 level tape.  The 
carriage of the Flexowriter does move, unlike the later Teletype Corp 
Model 33 and Model 35 where the carriage does not move, instead the 
type cylinder moves (the 35 is surprisingly close in appearance to the 
Model 28 in those pictures, but Teletype Corp had gone to a beige color 
scheme by then).

With the Model 33 and 35, the print is made with a mechanism that is 
similar to the IBM Selectrics, except that it is cylindrical instead of 
spherical.  The Selectric typeballs themselves became superseded by 
Daisy Wheels.  On these machines, "carriage return" took on a different 
meaning from the older machines, but the mechanical settling times for 
the type heads were still substantial.  So we all learned to program in 
a carriage return before a linefeed since the platten rotation had a 
much faster settling time than the "carriage."

Paper tape was yet another story.  To edit a programming error, you 
would manually cut sections off of the original tape and splice in a 
corrected section, like what audiophiles used to do with reel-to-reel 
audio recording tapes.  Later, there were programs such as TECO that 
would "edit" for you.  TECO duplicates an input tape into an output 
tape up to the point you want an edit made.  You then punch the edited 
part in from the keyboard or memory, the input tape is advanced past 
the part you are replacing and then the duplication resumes for the 
rest of the tape.  You discard the input tape -- we must have cut down 
entire forests when writing programs.

Not all "paper" tape was paper, either.  The "boot tapes" that are used 
over and over were punched into mylar tapes.  Not all ASR can cut mylar 
tapes, either.   Yes, machines in that era crashed too :-), but more 
often the rebooting was for when they are taken down for the daily 
maintenance.  I'll bet the mylar tapes would have been great as brag 
tapes -- any wealthy hams here who had used mylar brag tapes?

73
Chen, W7AY

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