A digital pedal cross-brand standard for passing digital signals between multiple digital pedals. One pedal does the A/D early in the chain, then passes ADAT or SPDIF or AES/EBU to any other digital pedals, then one at the end of the chain does the D/A. Because really, how many times do you want these conversions happening in one signal chain? More than one conversion is way too many, so I don't use multiple digital pedals. Big argument in favor of a single multi-effects box, I know, but I like the idea of great modular specialized digital pedals, just not repeated conversions.