[GreenKeys] Carriage return questions

[Ralph Mowery]

On the model 15 printers it was returned by a spring.   You can not see
it,but there is a round metal can with a spring in it and a flat web
'string' wrapped around it.  Sort of like the recoil starter rope of a
lawnmower engine.   Then as it comes back to the left there is a 'dash pot'
that slows it down .  When the carriage comes back to the left the last
couple of inches it hits the dash pot and slows down much like the closer of
a screen door on your house.

One trick that some liked to try was to print an O some where on the line
as the carriage was going to the right, then as it was coming back to print
a period (.) to see if it could centered in the O.  Sort of like target
shooting.

The time delay is why for hams it was often recommended to send two CRs a
line feed, and one or two LTRS.
The two CRs was incase the first one was missed, and there needed to be at
least 2 non printing characters after the CR. Three were even better.

Ralph ku4pt


-----Original Message-----
From: greenkeys-bounces at mailman.qth.net
[mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Mike Dodd
Sent: Friday, May 15, 2020 10:09 AM
To: greenkeys at mailman.qth.net
Subject: [GreenKeys] Carriage return questions

Can someone refresh my memory about how the carriage in older TTYs and 
the type box in newer machines was moved to the start of a new line upon 
receipt of a CR character?

Was it a powered movement, or did a spring haul it back? Seems like it 
would have to be pretty quick -- perhaps only 0.28 seconds -- to get it 
moved before the next character after the CR LF sequence.

Just curious; it's been a long time since I saw one in action.

Thanks.

--- Mike N4CF