I would like to know how to map ports of a Digium TDM404B to

I would like to know how to map ports of a Digium TDM404B to specific extensions. The purpose is to use Asterisk@Home as a SIP gateway to a legacy PBX. For example I would like to map port one of the Digium TDM404B to an extension created as 3227. This includes all incoming calls and all outgoing calls. This would allow using the Asterisk@Home server to provide a SIP connection to the legacy PBX for in-house users and as a remote connection tool for offsite users. For example I would create a separate extension as 4227 for the remote tool and switch to the 4227 extension when the user wants to work from home instead of the office. I would disable Voice Mail on the legacy PBX so that Asterisk would provide voicemail in either scenario. All calls from Ext 3227 or 4227 woud need to forward to Port 1 of the Digium. This would allow users in-house to know which remote users is calling them. I guess that I could also put Ext 3227 (for local SIP Phone) and Ext 4227 (for remote SIP phone) it a queue named QUEUE227 and then the user could pickup the phone whether they are in-house or remote without requiring configuration changes. The TDM404B is the Digium 4-port FXO card. I will use its analog ports to interface with the legacy PBX.

I am a new Asterisk (and Asterisk@Home) user and have searching the forum and not found an answer for this. Thanks in advance for any help received.

You can use different contexts and extension s.