FSC-503 Momentary, Normally Closed Some manufacturers of keyboards and recording gear, such as Roland and Yamaha, set their keyboards to sustain and/or switch patches (and set their recorders to punch-in and out), when the foot switch BREAKS (rather than MAKES) a connection.
So, for gear made by Roland and Yamaha, or any other manufacturer that specifies a momentary, normally closed switch, Hosa's FSC-503 is the right one to choose. (looks identical to FSC-501 pictured above)
NOTE:
At the time of this writing, the only manufacturers specifying switches like the FSC-503 are Roland, Yamaha and Technics. As far as we know, most other major manufacturers specify switches like the FSC-502.
Some manufacturers, like Kurzweil and Korg, make keyboards and sound modules which check the foot switch jack during the startup self-diagnostic, and adjust themselves accordingly for whatever footswitch is connected at that time. For those keyboards, either the FSC-502 or the FSC-503 will work as long as you plug one of them in before you power-up. There are no standards for footswitch implementation, and music-equipment manufacturers are free to change their minds on this, so the only way to be sure which type of switch will work for your application is to read the equipment manual or call the equipment manufacturer.
