I’ve had lots of experience with the MP100’s and my advice would be that unless you are looking specifically for an MGCP device leave it alone.
The AudioCodes products don’t come with any call manager or gatekeeper products and we’ve had nightmares trying to get them to interoperate with anything else.
As I say, unless you specifically want MGCP, there are better – similarly price H.323 and SIP gateways on the market.
We’ve also used the Mediatrix stuff with some limited results.
Try Welltech (cheap), or Quintum (reliable and interoperable with everything).