My wiring closet is my office and I need a 24-port switch. I have an allied telesyn rapier layer 3 switch that I got for cheap. That was fun to play with but (1) I never really got around to using its ...

A telco rack is just 2 posts instead of 4, the holes line up the same and you mount it in either. A switch will just mount to the front (or more usually, the back) posts in the rack.