Mic-Mutes are the only 'toggle on' - 'toggle off' intercom muting system I know of.  Not only do they work great, they use the built-in handlebar control on the bike if possible (Goldwing) and are ultra reliable.  They work by enabling either rider to engage the mics or disengage them with a simple touch of the button or handlebar PTT, and they stay engaged or disengaged till you tap the button again.  Very cool.  No more 'Push and hold to talk' operation.  VERY cool.  Mine are 4 years old now, and are as reliable today as on the first day I used them.  Bill Morphy is a great guy to meet and work with.  Highly recommended products, and NOW they're available for the J&M CB2003 handlebar units.