Atlanta Open House Tomorrow

[Electronics Plus]

There are a couple of 56K-xxx AT&T keyboards there, but I counted, and there are only 6 wires in the female connector. There is not a fixed cable.

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Ethan Dicks
Sent: Thursday, August 11, 2016 8:25 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Atlanta Open House Tomorrow

On Wed, Aug 10, 2016 at 8:15 PM, Al Kossow <aek at bitsavers.org> wrote:
> If anyone goes there would you PLEASE look for a Qume 201 and 
> Televideo 965 keyboard for me

Likewise, I'm looking for a couple of AT&T/Teletype keyboards for my 5620/Blit and my 730+.  They do _not_ have a round DIN plug, which distinguishes them from 98% of what's out there.  They have an 8p8c connector ("RJ-45").

There are several matching keyboards with different numbers of keys (~98-103).  56K-341-AAN is one part number.  Keyboards that will work are the same ones used on the AT&T 4410 and Teletype 5410 terminal.

I'm also seeing part numbers in the technical drawings (http://www.brouhaha.com/~eric/retrocomputing/att/5620/att5620_eng.pdf
pp 87-95) like:
 56K224
 56K229
 56K230
 410896
 410967

It appears to have 6 of the 8 pins in use - serial in, serial out,
+5V, -12V, signal GND, and frame GND (it makes its own -5V for the MCU
from a zener diode on the -12V line).  All of this plus the 1.8432MHz crystal, suggest to me a simple async protocol.  This would make a keyboard emulator simple to construct once someone has sniffed the protocol.

One is good.  Two is better.

Thanks,

-ethan