I'd like to use FreeSWITCH as my private bridge between SIP and GSM.

However, I consider USB modems to be a security threat, since they frequently have their own storage (can work as pendrives), have a black-box baseband and are hardly ever patched.

For that reason, I'd like to connect my USB modem to a separate machine (maybe an OpenWRT router) and connect that machine to my main FreeSWITCH machine over Ethernet. 

How would I set that up? Can mod_gsmopen be run alone, or would I have to install a separate instance of FreeSWITCH on that second machine?

Thanks!

PS. I'm still trying to wrap my head around FreeSWITCH, so please be forgiving. :)