Do you have physical access to these hardware pieces? If so, grab the company and any model numbers you can find. Look them up online or call the appropriate companies.

Switches and routers both have Console, AUX, Serial, RJ45, etc [physical] ports. Some even have Fiber, piggy-back/daisy-chain and so on.

There is a router involved if your traffic is going outside your Local Area Network (LAN). If all you can access are the 30 machines in your room, then a router may not exist. (it still COULD exist) If you can utilize an outside resource, such as Google, then a Router is sitting somewhere.

A switch operates at Layer 2 (MAC Address), while a Router performs its operations based upon Layer 3 (IP Address).

If all machines have two network connections, things can be a tad more complex.

Good luck!

Oh, and asking the company which set-up the environment is definitely an avenue I would consider.