[GLLUG] Mobile Mouse

[Marr]

On Saturday 24 March 2012 17:18:17 Richard Houser wrote:
> USB doesn't carry a ps2 signal, and there are no spare wires to just do a
> pin swap like you propose.

Are you familiar with the PS/2 pinout? Since there are only 4 of 6 pins used 
in the conventional case, and since USB has 4 pins, there is no issue of 
"spare wires", so I'm not quite sure what you're saying here.

The adapter I'm suggesting (to adapt a USB _peripheral_ to a PS/2 _host_ 
connection) is a very simple pin-for-pin re-mapping, as described here:

   http://pinouts.ru/InputCables/usb_ps2_mouse_pinout.shtml

In fact, I just grabbed 2 of my adapters of that type, one from a Kensington 
trackball and another from a Logitech trackball and electrically "rang" them. 
Unsurprisingly, they both match that website's wire re-mapping exactly.

Chick: There's an important note on that website: "It works only with device 
which supports both interfaces (USB & PS/2)."  So such an adapter may or may 
not work for you, depending on what sort of input device you wind up using. 
But it's certainly worth a try as a "Plan B" if nobody else comes through with 
something.

> Those adapters would have to have relied on
> additional, proprietary electronics in the mouse they were paired with,
> just like the reverse direction.

Assuming I understand you correctly, that's simply not true. Going from a 
PS/2-only device to USB at the PC end is harder than going from a USB device 
to PS/2 at the PC end because in the former case, the peripheral would not 
support USB _protocol_, hence the need for electronics in the "adapter" cable.

> You can find affordable ps2 dev to USB active converters, but I've never
> seen the reverse.

My experience is the exact opposite. Adapters for USB peripherals to PS/2 host 
connections are a dime-a-dozen (because they contain no active electronics). 
It's the cables/adapters that are used from a PS/2 peripheral to a USB host 
which are more expensive (i.e. because they require more than just some pin 
re-mapping). Not only are they more expensive, but they're very spotty as to 
how well they work in various OSes and conditions (e.g. with KVM switches).

But we're way off-topic, because all Chick needs, if it is to work with his 
input device at all, is the stone-simple, cheap, wire-remapping adapter.

Bill