You still using ADAT's???? Why?????
They need a synch cable between them. One will act as a master and the other will synch up to it.
It's very easy, and it works flawlessly.
Loudboy
get a lightpipe connector cable and use fiber optic technology to connect them. It's not too expensive. My boss uses 4 Alesis ADATs together with the top being master and the next 3 slaved to it and a BRC controller for all of them. Its pretty easy to do and they feed off as one unit to a larger mixer too using a 1/4 to (giant rectangular multipin thing). The thing I reference has a name, which I'm sure someone will fill in and it basically allows you to work with 32 tracks I believe without a huge 32 jack snake. And yes, ADAT is cheap and still useful, even if its a little more difficult to deal with (error messages galore) Be careful of the dirty head message. It costs like $100-125 to get the heads cleaned but with research and the right equipment you can do it for $2.50 yourself.