My Yamaha 101 has an RCA jack dedicated to a subwoofer I believe it is a mono cable that would be conneted. Don't think that a subwoofer connects via a digital connection but I may be way off on that.
The 101 also has a jack on the back that connects to a jack on a Yamaha subwoofer called a system connector that would allow the Yamaha subwoofer to be turned off via the remote.
I just purchased a cable from radio shack that would allow me to hook up my soundbar to one of my existing subwoofers that have the push in type connectors .The wire has a RCA plug on one end and the other end is stripped forming two stranded ends so I can push them into the subwoofer connectors. Haven't done it yet though.