I have a site that is far away in a small town that the carrier can not offer a PRI or T1 CAS. So, I have to stick with the 8 DID trunk and 8 COT trunks that currently go into a Nortel option 11 PBX. I want to convert the site to VoIP so I need to figure out what type of card either FXS or FXO the COT trunks will need. I know the DID trunks will need a FXS card and I think the COT trunks will use a FXO card is that correct?