z68 extreme4 ps/2 port

[uszkanni]

Trying to connect both mouse and keyboard to rear ps/2 port (via Y adapter), but only keyboard works. Mouse or keyboard will work if plugged in separately. Both work via same Y adapter on laptop. Does the ps/2 port support simultaneous mouse and keyboard? Do I need a special adapter? Didn't see anything on Asrock's website or in the user manual on this.

Thanks.