Post by thread:PS2 to USB

> > Got that after I discovered Dell Lattitude (600?) laptops have every port > > (even serial & parallel) except PS2. Odd. > lots of laptops have dropped external ps/2 ports, the systems to make > internal and external appear as one ps/2 device and to allow either a > keyboard,a mouse or a keyboard and a mouse with a special splitter on the > same port were in my experiance quirky at best (especially with hotplugging > or trying to use internal and external at once) and i guess the laptop > makers decided it was easier to just use USB. The PS/2 keyboard mouse splitters aren't really anything special. It's really the same pins for each, but one has a diode inside (don't remember which one). The PS/2 ports aren't meant to be hot-pluggable, so I'm not suprised that you had problems doing that. In my experience, the KEYBOARD can usually be unplugged, and re-plugged without problems, but not the mouse, and never both on a splitter. A friend has an older IBM thinkpad, and he tried a couple of USB-PS/2 (mouse and keyboard) converters. One was a cheap no-name, the other was a COMPAQ brand. Neither worked properly UNTIL he tried a different mouse. He was using a microsoft explorer mouse (with more than 3 buttons). Go figure.

> The PS/2 keyboard mouse splitters aren't really anything special. It's > really the same pins for each, but one has a diode inside (don't remember > which one). i thought they used the two spare pins, ofc there may have been two different designs (which would explain some splitters not working with some laptops) > > The PS/2 ports aren't meant to be hot-pluggable, so I'm not suprised that > you had problems doing that. In my experience, the KEYBOARD can > usually be > unplugged, and re-plugged without problems, but not the mouse, and never > both on a splitter. i'm sure i've seen latop manuals say otherwise > > A friend has an older IBM thinkpad, and he tried a couple of USB-PS/2 > (mouse and keyboard) converters. One was a cheap no-name, the other was a > COMPAQ brand. Neither worked properly UNTIL he tried a different mouse. > He was using a microsoft explorer mouse (with more than 3 buttons). Go > figure. and i found the same issue with a ps/2 cherry keyboard (though i only tried one adaptor) whereas with a crappy keyboard i had it worked fine. my guess is theese splitters are doing something like powering the device off 3.3V or powering it off 5V but using 3.3V signal levels. Either that or there is something nasty about how they implement the protocol. Since this is the piclist maybe i should try doing a 2550 based converter and see if i can get it working well :).

en.wikipedia.org/wiki/PS/2_connector No diode. Just different pins used for the mouse clk/data. peter green wrote: {Quote hidden}>>The PS/2 keyboard mouse splitters aren't really anything special. It's >>really the same pins for each, but one has a diode inside (don't remember >>which one). > > i thought they used the two spare pins, ofc there may have been two > different designs (which would explain some splitters not working with some > laptops) > > >>The PS/2 ports aren't meant to be hot-pluggable, so I'm not suprised that >>you had problems doing that. In my experience, the KEYBOARD can >>usually be >>unplugged, and re-plugged without problems, but not the mouse, and never >>both on a splitter. > > i'm sure i've seen latop manuals say otherwise > > >>A friend has an older IBM thinkpad, and he tried a couple of USB-PS/2 >>(mouse and keyboard) converters. One was a cheap no-name, the other was a >>COMPAQ brand. Neither worked properly UNTIL he tried a different mouse. >>He was using a microsoft explorer mouse (with more than 3 buttons). Go >>figure. > > > and i found the same issue with a ps/2 cherry keyboard (though i only tried > one adaptor) whereas with a crappy keyboard i had it worked fine. > > my guess is theese splitters are doing something like powering the device > off 3.3V or powering it off 5V but using 3.3V signal levels. Either that or > there is something nasty about how they implement the protocol. Since this > is the piclist maybe i should try doing a 2550 based converter and see if i > can get it working well :). >