I found this pretty cool gadget at Academy. This may not be news to everyone, but it's worth mentioning.
This timer is designed to time training bouts and workouts for boxers, and I don't see why it wouldn't work equally well for fencing.
It can be adjusted for up to 12 rounds of 2 or 3 minutes with breaks 30 or 60 seconds long.
The stop/start button will pause the timer.
I think it was $10.
http://store.everlastboxing.com/ever...ing-timer.html