Which shows the end as a USB (for mouse and keyboard) or a PS/2 for mouse and an adapter to PS/2 for keyboard. It might be easier to guess just the USB connections (ground, data+, data-, and +5V), possibly just from writing on the PCB of the receiver.
Ground is easy to spot since it is usually large areas of the PCB. 2 of the wires will be this.
The other 2 wires that connect together are for +5V, which just leads 4 data lines.
You might even get away with connecting USB ground and +5V, then try sets for the data +/- until the PC detects the device. Note this might destroy the universe (or more likely only the receiver and/or that USB port if anything), so beware. But, I've connected USB data lines backwards before and had no ill effect (besides it not working until I connected it properly).
-Richard L. Owens, author of the uberOptions mod for SetPoint. Unlock the options of your SetPoint-controlled device! mirror