Apple II Parallel Printer Interface and the "Spare" slots

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Joined: Aug 3 2015
Posts: 14

I picked up this card to put into my Apple II and noticed that it had chips in the "Spare" slots (over to the left on the card)
All the other ones I have seen have had the spare slots unused. Could someone help me with what they do?
Thanks!
-Neil Moore

AttachmentSize
Parallel Printer Interface Front4.76 MB
Parallel Printer Interface Back (showing rework)4.74 MB

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speedyG's picture
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Joined: Nov 16 2011
Posts: 2413
Re: Apple II Parallel Printer Interface and the "Spare" slots

Hello NeilMoore,

welcome to the community....

the purpose of the modification is adjusting the handshaking
signals between printer and computer.

Some printers demand negativ handshaking signals instead of the
positiv signals used at the card. So first purpose is to invert
that handshaking signals and second purpose sometimes also a delay
is requested by the printer... so that is the second purpose of the modification.

sincerely speedyG

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In early days I had a lot of money but no time - now I have no money but a lot of time....
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Posts: 14
Re: Apple II Parallel Printer Interface and the "Spare" slots

Thanks SpeedyG!
Are there any docs out there that show me how to re-create the mods and for which printer? I'm curious as to which printer this was modded for.
-Neil

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Joined: Aug 3 2015
Posts: 14
Re: Apple II Parallel Printer Interface and the "Spare" slots

Thanks SpeedyG!
Are there any docs out there that show me how to re-create the mods and for which printer? I'm curious as to which printer this was modded for.
-Neil

speedyG's picture
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Joined: Nov 16 2011
Posts: 2413
Re: Apple II Parallel Printer Interface and the "Spare" slots

Hello NeilMoore,
before you start removing the modification - first inspect what kind of printer you have
that will work with the software of the Apple you have....

And when you know which printer you can use - then next will be -
to check the documentation of the printer to see what kind of
connection it establishs....
maybe you might need that mod for your printer too ???
It´s only recommended to remove the modification
if you know that your printer demands the removal of the mod....

if you don´t know about the printer tell here what printer you want to use...
maybe a member has the missing documents and can tell you if the mod
is recommended or not...
sincerely speedyG

__________________

In early days I had a lot of money but no time - now I have no money but a lot of time....
the second part includes less friends but a lot more joy on life....

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Joined: Aug 3 2015
Posts: 14
Re: Apple II Parallel Printer Interface and the "Spare" slots

Hi!
I am working this kinda backwards, I am building an era correct Apple ][ rig. So I have a lot of flexibility in the printer area. I am looking for a printer that will work with this card and learn a bit about the inner workings of the Interface in the process!
Thanks to you, I have an idea what the chips were used for, I'll see if I can track down what the chip and re-work change in the operation of the card and then find a matching printer.
Thanks!
-Neil

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Joined: Dec 10 2011
Posts: 667
Re: Apple II Parallel Printer Interface and the "Spare" slots

NeilMoore wrote:

I picked up this card to put into my Apple II and noticed that it had chips in the "Spare" slots (over to the left on the card)
All the other ones I have seen have had the spare slots unused. Could someone help me with what they do?
Thanks!
-Neil Moore

Here is the Manual for this Card.

I actually got One of these cards, and Two of the Second Generation, Parallel Interface Card in a Batch of 20 Apple ][ Cards.

Just last month I got a Third, Second Generation, Parallel Interface Card, with Manual.

MarkO

speedyG's picture
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Joined: Nov 16 2011
Posts: 2413
Re: Apple II Parallel Printer Interface and the "Spare" slots

If you still want to remove the modification, also pay attention to the
wired "configuration" plug ! It´s not standard that way. The manual - of which
MarkO passed over the link - contains more information about the regular used plugs.
sincerely
speedyG

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In early days I had a lot of money but no time - now I have no money but a lot of time....
the second part includes less friends but a lot more joy on life....

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Posts: 14
Re: Apple II Parallel Printer Interface and the "Spare" slots

I'll probably not remove the mod, but go and find the printer that works with it the way it is. I think it looks kinda cool with all the rework on it.