PRS01 paper tape was(Re: PDP-8/e restoration (was Re: Oscilloscopes)`)

From: <(>
Date: Sun Dec 26 17:08:00 1999

>>I still have this pr/s01
>>20mA portable papertape reader, but I still know nothing about it,
>>baud rate. I haven't yet hauled a 'scope out to the place the -8's are at.
>>That's one of the next steps.

>They made two models: "A" version which is 20mA 300 baud. and a "B" version
>which is 20mA 2400 baud. I can post pinouts for the group if needed once I
>get the full model number.

Mine started out life as the 300 baud version, but was "field modified"
to 2400 baud by changing some of the timing capacitors. (No crystals here,
the baud rate is set by a capacitor and tweaked with a variable resistor.)

It was also "field modified" to RS-232 by adding a small circuit board to
the 0.1"-pitch header inside. (That was done by me!) The circuitry inside
is really quite simple, just plain old TTL and some optocouplers for the
20mA interface.

What *I* like about the PR/S01 is:

1. Very portable, down to the carrying handle on the end :-).

2. It doesn't use a bulb, but instead a small array of infrared LED's for
scanning. For those who've had to deal with loose bulb connections or dead
bulbs while in the field, this is a *real* godsend.

 Tim Shoppa                        Email:
 Trailing Edge Technology          WWW:
 7328 Bradley Blvd		   Voice: 301-767-5917
 Bethesda, MD, USA 20817           Fax:   301-767-5927
Received on Sun Dec 26 1999 - 17:08:00 GMT

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