[plug] PS2 - DB9

[Brad Campbell]

David Campbell wrote:
> 
> From:                   "Shackleton, Kevin" <kshackleton at agric.wa.gov.au>
> To:                     plug at linux.org.au
> Subject:                RE: [plug] PS2 - DB9
> Date sent:              Tue, 24 Nov 1998 16:06:01 +0800
> Send reply to:          plug at linux.org.au
> 
> > To throw more darkness on the issue . .
> >
> > I have a PS/2 header on my motherboard (4 * 2 with 2 missing pins).  I
> > got hold of a PS/2 & parallel port backplane strip.  But when I try to
> > plug a PS/2 mouse into it, the keyboard locks up and the PC strongly
> > objects.  I'd say there are a couple of ways the mobo headers are wired.
> 
> For ASUS mainboards there is a few BIOS settings which need to be set right
> otherwise it will result in keyboard lockups as stated. I need to look at my
> home machine to find out what I have my mainboard set to.
> 

Ok. First post to PLUG! Hi Everyone :p)

PS2 mouse uses the same synchronous interface as the Keyboard.
Serial mouse generaly use 1200,8,n,1 RS232 TX Only.
You will generaly find that PS2/Serial mice detect what they are
connected to by
looking for the a response from the keyboard controller to a request by
the mouse.
Sometimes they also just look for an RS232 handshaking signal.
Therefore, dual mice come with an adaptor that routes the appropriate
pins to the 
corect mice signals.
The PS/2 mouse controller is the keyboard controller. Since the first
ps/2 machine the
standard PC 8042 that controlls the kbd, has a second channel, with an
IRQ of 12 to drive
a mouse.
Most pentium boards come with a ps/2 interface, and recently they also
come with the correct
adaptor to place the connector on the back of the machine. ASUS were
notorious for not doing
this, meaning you had to go to ASUS to buy the cable.
ASUS also make all thier serial/paralell cables non-compatible with
generic motherboards.

To sum up, a PS2 mouse can not be connected to an RS232 port or
vice/versa, however dual mode
mice are available, and will usually only work with the adaptor they are
supplied with.
ie My trackball comes with a lead with a D9 on the end of it, then a D9
to 6 pin mini DIN (PS/2)
6 Inch adaptor lead.


Hope that clears things up.



-- 
-----------------------------------
Brad Campbell
Technical Manager

Seme Electrical Engineering Co
59 Collingwood St Osborne Park 6017
Western Australia
Ph    :-+61 8 9445 2577
Fax   :-+61 8 9244 1327
Email :- brad at seme.com.au

  /"\
  \ /
   X  ASCII RIBBON CAMPAIGN
  / \ AGAINST HTML MAIL