I have one. It doesn't really work like the Fostex. I swear it doesn't. The Boss was the first thing I tried because someone else said it worked. It. Doesn't. Pinky swear. Guess I'll just hunker down and repair the one I have. If I can.
Of course you may mean the Boss 5L That is the "latching" type. The "non-latching" type requires you to have the pedal depressed for the duration of your punch in. Continually holding it down, as it were. I can't concentrate on the performance when I have to have my foot pressed on the switch. Did you mean the Boss 5L?
FSC-502 Momentary, Normally Open. A great sustain pedal or patch-advance switch for electronic keyboards and synthesizers. Also great as a punch-in/out switch for multi-track recorders such as those made by Fostex and Tascam or a start/stop switch for drum machines and sequencers.