An important 'heads up' for Pro Tools users. Please make note that an ADATBridge I/O should be connected to the Primary (MixCore) card in a ProTools system. The ADATBridge can only clock to light pipe when connected to the MixCore. The option is not even available in PT's Session Setup window when connected to a secondary (MixFarm, etc.) card. While the ADATBridge can be connected to the secondary card, clocking properly to incoming optical will be unreliable and/or impossible. Even when a common/"house sync" clock reference (USD, AardsyncII, etc.) is used, problems will occur. Most commonly, clicks and pops during ADAT playback, and crackling white noise when ADAT's are on input (rec.-enabled).I first experienced these symptoms with a PTMixPlus system, and AD8000 on the MixCore, an ADATBridge on the MixFarm, 2 ADAT's and a BRC. Even when sending word clock (from Bridge or AD8000) to the BRC, record-enabling ADAT's cause PT to receive white noise only.