[Freeswitch-users] Asterisk and Freeswitch co-existence?

I am new to Freeswitch. Before starting with Freeswitch, I had, and still do, an Asterisk (Switchvox) on the LAN. What changes to the Freeswitch config files do I need to make so that it can co-exist with the Asterisk box on the same LAN? I don't mean collaborate or interoperate, just co-exist. I know I need to change the SIP port number. Is there a document which describes this environment? Thanks, Lars