[GreenKeys] The last of the Pasco 35 ASR photos .. for a while

[Jack]

I notice the 35 typing unit does not have a print-suppress solenoid. I
assume the 9140 did the "blinding" on the internal loop. I have
a Frederick "Selcal" that actually has an in-loop and out-loop. It
regenerates the incoming data some that when it unblinds the
printer doesn't garble. This is the TTL chip version of the Selcal, not
the one with a thousand 2N404 transistors.









-----Original Message-----
From: GreenKeys [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Jim
Haynes
Sent: Monday, August 10, 2015 2:05 PM
To: Pete Lancashire <pete at petelancashire.com>
Cc: greenkeys <GreenKeys at mailman.qth.net>
Subject: Re: [GreenKeys] The last of the Pasco 35 ASR photos .. for a while

That's a lot of boards, some of them very thinly populated.  Looks like for
that product Teletype was still using the somewhat standard 36 pin connector
with the edge pins on .156" centers.

That started out as a card with 15 edge pins.  Sometime in the early 1960s
they decided they needed a larger card, so they went to the 36 pin design
and had a card guide that could snap on to the middle of the connector to
allow it to hold two 15-pin cards or one 36-pin card.  I was rather
distressed that in the mid 1960s they were still using the original
standards for line widths and component spacings, leading to very low
density of parts on the boards. I see that by the time of ICs in the 1970s
they had been forced to go to narrower lines and tighter spacings, but were
still using the same edge connectors.

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