HP 12653A line printer interface

COURYHOUSE at aol.com COURYHOUSE at aol.com
Sun Jul 16 18:58:21 CDT 2017

if the one I think it is... 300 lpm but if  you are printing   only  one 
zone  on the left  side 1000 lpm
if  one was  close  to  AZ  I would buy it.   I have great  fond memories 
of that  unit ! we had on our hp  2000.
Ed#  _www.smecc.org_ (http://www.smecc.org)  
In a message dated 7/16/2017 4:54:59 P.M. US Mountain Standard Time,  
cctalk at classiccmp.org writes:

I do  indeed have the printer. Found it on the weekend. No sign of the 
interface  card or cable yet though. 

David Collins

(Sent from out of  office)

> On 14 Jul 2017, at 6:02 pm, CuriousMarc via cctalk  
<cctalk at classiccmp.org> wrote:
> Ah, thanks, I learned  something. The HP 2767 is a weird beast - line drum
> printer but only  80 columns, from what I glean from hpmuseum.net. David
> (Collins), do  you have the printer?
> Marc
> -----Original  Message-----
> From: J. David Bryan [mailto:jdbryan at acm.org] 
>  Sent: Tuesday, July 11, 2017 11:12 AM
> To: CuriousMarc
> Cc:  Classic Computing List
> Subject: Re: HP 12653A line printer  interface
> Marc,
>> On Monday, July  10, 2017 at 22:24, CuriousMarc wrote:
>> I thought I  did, but what I have is the HP 12845B Line Printer 
>> interface  card, for which I could find the documentation.
> Thanks for  checking.  Yes, that does seem to be the more common card.   
> far as I know, the 12653A was used only for the HP 2767 (a  rebranded Data
> Products 2310), whereas the 12845B was used for a  number of other HP
> printers.
>> Reading  some more, it is meant for the 2607/261x series of printers, 
>>  which apparently use a narrower 7 bit interface (the 12566 is a 16 bit  
>> interface card).
> Which is all a bit odd, as the  2767 also uses 7 bits for data.  Unlike 
> other printers that  use differential interfaces, the 2767 uses 
> TTL-level  (more or less) drivers and receivers, which may explain the 
use of
> the  microcircuit-based interface.
> The 2767 signal drivers are  adjustable for a 3- to 8-volt output level, 
> perhaps the 12635A  "modification" was to clip the inputs to avoid 
> the standard  microcircuit receivers (7400 TTL with an absolute maximum 
> spec  of 5.5 V).  In the absence of a manual, I was hoping that a  
> would reveal the modification.
>> But maybe you can inspire yourself from it.
> The  existing 2767/12653 simulation was reverse-engineered from the
>  diagnostic and OS drivers.  Although it works, I was hoping for  
> more authoritative so that the code could serve as a  reference for the
> now-extinct hardware.
>      -- Dave

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