Ethernet connect - host to test?

If there is a better newsgroup for my question please let me know
but..

Is there a tool or cheap method to test physical ethernet connects?
I was hoping there was a reasonably priced tool that can check signal
strength/quality of the wires, similar to how the cable company checks
coax cable.

I am experiencing poor network connectivity from some offices around
the building here. Unless someone else has a recommendation how I can
go about to check into this problem. The switch has a green light for
a 10/100 connection. Any suggestions?

.