Q59861: 400 DPI Serial Mouse and Northgate Computers

Article: Q59861
Product(s): See article
Version(s): 1.00
Operating System(s): MS-DOS
Keyword(s): ENDUSER | | mspl13_basic
Last Modified: 2-MAY-1990

When the 400 PPI PS/2/Serial Mouse is installed on the 9-pin serial
port of some Northgate Computer, the mouse may not install.

When the 400 PPI PS/2/Serial Mouse is installed on the 9-pin serial
port as a serial mouse, it uses pins 2, 3, 4, 5, and 7 to communicate
with the serial port.

The other pins in the 9-pin connector are used when the PS/2 adapter
is connected to the mouse. Pin 8 of the built-in serial port, when set
to a logic zero, is 1 to 2 volts higher than the voltage that would be
present on an IBM compatible serial port. When a logic 1 is present on
pin 8 and the mouse is connected to a 9-pin serial port, the mouse
cannot reset. This prevents the mouse from installing.

To work around this problem, do either of the following:

1. Contact Northgate Technical Services at (800) 445-5037. They have
   found the cause of the problem and will work with you to make the
   necessary corrections to the motherboard.

2. Use a 9- to 25-pin serial adapter to eliminate the signal from pin
   8. To do this, you need to purchase the adapter from a local
   electronics store. This adapter has a 9-pin female connector on one
   end and a 25-pin male connector on the other end. Once you have the
   adapter perform the following steps:

   a. Attach the adapter you purchased to the built-in serial port of
      your computer.

   b. Attach the mouse to the 25- to 9-pin serial adapter that was
      supplied with your mouse.

   c. Attach this adapter to the 9- to 25-pin adapter that you have
      already attached to your computer.