Cisco UBR924

I have 2 Cisco ubr924 modems right now I have one modem hooked into phone system at one location into the CO ports and another modem in other location doing same thing it is working great. My question is I see there is a connection trunk feature on these modems what would this do for me compaired to what I am doing now?? Right now in the phone system on each end they just pick up that line and dial the extension and it goes to other modem and come’s into phone system pretty simple. I am just wondering if I do this Trunk if it would give me more feature’s or more line’s through 1 port? Thanks