Path: utzoo!attcan!uunet!pilchuck!ssc!markz
From: markz@ssc.UUCP (Mark Zenier)
Newsgroups: sci.electronics
Subject: Re: Info on some old terminals needed
Keywords: lear-siegler, memorex, soroc
Message-ID: <442@ssc.UUCP>
Date: 25 Oct 90 05:31:56 GMT
References: <271fe183-4c9sci.electronics@vpnet.chi.il.us> <2719@naucse.cse.nau.edu>
Organization: SSC, Inc., Seattle, WA
Lines: 51

In article <2719@naucse.cse.nau.edu>, rrw@naucse.cse.nau.edu (Robert Wier) writes:
> In article <271fe183-4c9sci.electronics@vpnet.chi.il.us>, cgordon@vpnet.chi.il.us (Crash Gordon) writes:
> > Lear-Siegler ADM-3 -- This one is not configured for lowercase.  
> > I need to add a couple of 2102 RAMs
> > to add that extra bit to the frame buffer.  I think I also need an extension
> > to the character generator ROM.  Does anyone still sell 2102s?  And where
> > might I come across the ROM (or even just the format; I've got a burner and
> > could cob up a lowercase font...)  (OK, so I'm bored :-)
> > 
>   I also have an LSI ADM3A (built from a KIT .. anybody remember 
> those?).  

Get the fastest 2102 you can find, or your screen will have ghost character
and other strange stuff.

Some things to know about the ADM3

1.  the ring indicator pin on the modem connector is connected to the
diagnostic memory readback.  If this become active (ttl gnd?), the
contents of the display memory are dumped out the serial port.
If your modem uses this, cut the trace.

2.  the lower case rom is nonstandard. (At this late date, it doesn't
matter much).  The character select inputs are inverted.

3. If you have the lower case rom, and disable the control character
decoder (can't find my notes, arrgh), it makes a cheap line monitor.


GI RO-3-2513

1  NC (-12v)                 24 5v
2  NC                        23 NC
3  NC                        22 A9 character select
4  O1 output (right column)  21 A8    "        "
5  O2                        20 A7    "        "
6  O3                        19 A6    "        "
7  O4                        18 A5    "        "
8  O5 output (left column)   17 A4    "        "
9  NC                        16 A3 row select
10 Gnd                       15 A2  "    "
11 /CE                       14 A1  "    "
12 NC (-5v)                  13 NC

1. row address 000 not used, row 001 top, row 111 bottom
2. for the lower case rom, the character select  0xxxxx is graphic 
representation of the control characters, the character select  1xxxxx 
is the printable characters.


markz@ssc.uucp