Students are not permitted to use the headphone inputs on the rear of the computers.
Please use the headphone socket on the Scarlett Solo audio interface.
Headphones in general come with a 3.5mm mini-jack.
The interface requires you use headphones with 6.5mm stereo jack, or alternatively a 3.5mm mini jack to 6.5mm stereo jack adapter for use with headphones for converting a mini jack to a 1/4″ jack plug.
You can provide your own, or alternatively buy one from SEM.
Stereo jack adapters cost £2.00 through SEM
Reference: SEM Jack Adapter