[comp.sys.amiga] Extending Amiga Keyboard Cable

ee173way@sdcc3.ucsd.EDU (John Schultz) (01/08/87)

References:


Why can't I use a longer handset cable with my keyboard? 
I've tried 25 feet, then 12, haven't tried 6 yet.  Anyway, RKM says it
can be done, but using 25, or even 12 foot cables, the keyboard is
unable to establish communications with the computer, the red caps
lock led just comes on a constant red (no flashing) which probably
means something (haven't looked it up yet...).  So what is the
limit?

John
7OHN

kagle@batcomputer.tn.cornell.edu (Jonathan C. Kagle) (01/08/87)

In article <3692@sdcc3.ucsd.EDU> ee173way@sdcc3.ucsd.edu.UUCP (John Schultz) writes:
>Why can't I use a longer handset cable with my keyboard? 
>I've tried 25 feet, then 12, haven't tried 6 yet.  Anyway, RKM says it
>can be done, but using 25, or even 12 foot cables, the keyboard is
>unable to establish communications with the computer, the red caps
>lock led just comes on a constant red (no flashing) which probably
>means something (haven't looked it up yet...).  So what is the
>limit?
>
>John
>7OHN

	When I tried to do the same thing with my early-vintage Amiga, I had
the same problem.  When I tried a colleague's Amiga keyboard with my Amiga
and extended cable, everything worked.  On closer, inspection, there are at
least three release versions of the Amiga keyboard- the two newest ones seem
to work with extended cables.

	1)  Keyboard with deeply sculpted F and J keys and a dull checkmark
	    logo in the corner (Mine didn't even have a serial number).  
	    This type doesn't seem to work.

	2)  Keyboard with deeply sculpted F and J keys and a shiny checkmark
	    logo in the corner.  This type works.

	3)  Keyboard with raised dots on the D and K keys and a shiny check-
	    mark logo in the corner.  This type also works.

I am not sure that these external features would always correspond to the
internal circuitry; perhaps someone at Commodore could enlighten us as to the
exact serial numbers which had the old electronics?

Jon
7OHN

hutch@sdcsvax.UCSD.EDU (Jim Hutchison) (01/08/87)

In article <3692@sdcc3.ucsd.EDU> ee173way@sdcc3.ucsd.edu.UUCP (John Schultz) writes:
>Why can't I use a longer handset cable with my keyboard? 
On guru consultation, I got this advice:
You Must Seek A Greater Power...

In simple truth, try either a beefier cable, or a power supply at your
keyboard (for truly monumental distances).  Simple phone cable is too
wimpy.  The smarts in the keyboard need more juice.
>... the red caps
>lock led just comes on a constant red (no flashing) which probably
>means something (haven't looked it up yet...).
Now, that's a dam* nice diagnostic!

-- 
    Jim Hutchison   		UUCP:	{dcdwest,ucbvax}!sdcsvax!hutch
		    		ARPA:	Hutch@sdcsvax.ucsd.edu
Madness, where would we be without it?  sane.  DES drugs cia ussr raygun laser

cmcmanis@sun.uucp (Chuck McManis) (01/08/87)

In article <3692@sdcc3.ucsd.EDU>, ee173way@sdcc3.ucsd.EDU (John Schultz) writes:
> Why can't I use a longer handset cable with my keyboard? 
> John

Because the 5 volt levels that the Amiga use are only 2 volt levels after 
travelling out an back. The easiest way to fix this for short runs is
to add a 5 volt supply to the keyboard. (The data lines draw little enough
current that they can go the distance) You have to take apart your
keyboard to do this though. 

-- 
--Chuck McManis
uucp: {anywhere}!sun!cmcmanis   BIX: cmcmanis  ARPAnet: cmcmanis@sun.com
These opinions are my own and no one elses, but you knew that didn't you.

czhj@vax1.ccs.cornell.edu (Ted ) (01/08/87)

Did you turn the computer off before you changed cables?

yerazuws@rpics.RPI.EDU (Crah) (01/09/87)

In article <2433@sdcsvax.UCSD.EDU>, hutch@sdcsvax.UCSD.EDU (Jim Hutchison) writes:
> In article <3692@sdcc3.ucsd.EDU> ee173way@sdcc3.ucsd.edu.UUCP (John Schultz) writes:
> >Why can't I use a longer handset cable with my keyboard? 
> On guru consultation, I got this advice:
> You Must Seek A Greater Power...
> 
> In simple truth, try either a beefier cable, or a power supply at your
> keyboard (for truly monumental distances).  Simple phone cable is too
> wimpy.  The smarts in the keyboard need more juice.

VT220 keyboards (actually, all of the DEC terminals that use various
flavors of LK201 keyboard) have the same problem - they pull too much
power to use a standard phone cord, even though they use telephone 
modular connectors on the ends.
	
Solution: Get some cable(s) from DEC and modular/modular double female
inline connectors from Radio shack.  String 'em around the house, out 
to the garden, etc.  :-)
	
	-Bill Yerazunis

ee173way@sdcc3.ucsd.EDU (John Schultz) (01/10/87)

Yes, the computer was off, but this has nothing to do with the
problem as the computer is able to re-establish communications if
the keyboard is disconnected, although it may restart the system.
It would appear that my clunky keyboard is too old and the internal
electronics are too anemic to handle anything longer than the
original cable (without a kludgy power boost).

The computer was purchased a year ago october, the first day they
arrived in La Jolla.  The keyboard has raised F and J keys (instead
of the normal D and K) and has a "clunky" feel to it.  Also, some of
the keys "squeak".  It has the dull checkmark, and absolutely no
serial number or product description (although there exists an
indented location for the sticker on the back...).

As usual, he who buys first is usually bent over, with no course for
correction, but this is the price one must pay if he wants to be
first...

John
7OHN

grr@cbmvax.cbm.UUCP (George Robbins) (01/11/87)

In article <1969@batcomputer.tn.cornell.edu> kagle@batcomputer.UUCP (Jonathan C. Kagle) writes:
>In article <3692@sdcc3.ucsd.EDU> ee173way@sdcc3.ucsd.edu.UUCP (John Schultz) writes:
>>Why can't I use a longer handset cable with my keyboard? 
>>I've tried 25 feet, then 12, haven't tried 6 yet.  Anyway, RKM says it
>>can be done, but using 25, or even 12 foot cables, the keyboard is
>
>	When I tried to do the same thing with my early-vintage Amiga, I had
>the same problem.  When I tried a colleague's Amiga keyboard with my Amiga
>and extended cable, everything worked.  On closer, inspection, there are at
>least three release versions of the Amiga keyboard- the two newest ones seem
>to work with extended cables.
>
>I am not sure that these external features would always correspond to the
>internal circuitry; perhaps someone at Commodore could enlighten us as to the
>exact serial numbers which had the old electronics?
>
>Jon

Well, there are only two significantly different keyboards for the Amiga.
The original is a little funny when multiple characters are pressed.  The
later version has improved pseudo rollover, and a deadman timer to reset
the keyboard if it hangs up due to static electricity or other distress.

Actually, I would guess that the older ones would be more tolerant of lower
voltages, but who knows!

Anyway, the big trick is to make sure that the cable you use has stranded
wire in it.  Real Bell telephone spiral cords, especially the handset ones
use a tinsel conductor that doesn't conduct power all that well.

The radio shack modular cable that comes in a real contains stranded wire,
but I've never tried it on an Amiga so no promises...

-- 
George Robbins - now working for,	uucp: {ihnp4|seismo|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@seismo.css.GOV
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)

wtm@neoucom.UUCP (Bill Mayhew) (01/14/87)

	After glancing through the RKM, it seems like it would be a
good idea to power off when changing the cable.  In general,
shutting down is probably a good idea in that some bizarre
circumstance could cause a short.  Sencond of all, the Amiga and
the keyboard exchange data packets.  For instance one raw event
when you press a key and another raw event when you release the
key.  It is possible to cause a garbage packet while
unplugging/plugging in the connector and wind up with your keyboard
out of sync, therefore not being able to rouse the attention of the
computer.

	As far as making a booster power supply goes, I don't think
it is a real good idea.  If you feel compelled, I think I'd use a
double female connector at the keyboard end and a short length of
wire to splice in the power pack leads.  This will also allow you
to  disconnect the  power coming from the Amiga without needing to
modify the keyboard itself.

	The best way would be to use a short piece of square phone
wire from the computer to a sqare wire-to-screw terminal adapter
and then run whatever gauge wire strikes your fancy to the same
kind of adapter where you want to plug in your keyboard.

	Of course, if you take anything above to heart and try to
modify your computer you are assuming complete responsibility if
you damage your equipment (University Policy Disclaimer).

  --Bill

Bill Mayhew
Division of Basic Medical Sciences
Northeastern Ohio Universities' College of Medicine
Rootstown, OH  44272  USA    phone:  216-325-2511
(wtm@neoucom.UUCP    ...!cbatt!neoucom!wtm)