24 Ctu Ringtone

What game does the Ctu Ringtone from the series 24 come from?

I know it was about the same time as doom and think it was played in dos. It involved a man landing in a space ship and each level was either a planet or a bit of a planet. Please help its really bugging me!

Not sure what game but it’s a real cisco ip telephone tone.

CTU Phone Ring From 24