I am trying to add a RB411a as a wireless access point to a network that uses a Cisco 3750g switch.
When I plug in the RB, the switch seems to block all traffic to it.
I can successfully communicate with the RB if I plug directly in to it with my laptop (using a POE), but when I plug into the switch, nothing passes. I can't even ping it. If I plug my laptop into the switch, it works and I can get on the network. To me, this is strange behavior. I called the company who put the network in, and they told me that only Cisco AP's can be used on a Cisco network. That sounds like B.S. to me. Anybody heard of that before?

They are not telling you the truth. They could have some kind of port security turned on. Cisco supports many different types.

But if you have management access to the switch and know what you are doing, it should work fine with Mikrotik ethernet ports. I have many RouterBoards plugged into a variety of Cisco switches. They work just fine. Without management access or their support, you are locked out.

Tom