Okay, I didn't dig out a mouse or keyboard and count the pins, but it's still a DIN connector, both the 6-pin PS2 mouse and keyboard connectors, as well as the 5-pin DIN connector that
@Jordan Dawes posted. There are many variations on this theme:
The "slotted" female contacts conceal two-bladed forks that mate with round pins on the male plug. Pretty reliable connector, although it could benefit from a positive push-to-release latching mechanism to keep the plug from falling out of its mating socket at the slightest tug on the cable. Maybe some variations implement that, but I don't know from first-hand experience.
I prefer the considerably larger, but more rugged, XLR connectors, which are usually 3-pin but also available with as many as five pins:
.
Hop