Key Digital ES381 - Manual (Page 6)

2 ABOUT THE USBcount50
2.1 General
The USBcount50 has been designed to allow a broad range of input
frequencies and pulses to be measured. The input stage supply is
programmable to allow the counter to work in circuits generating
various Voh levels.
Each USBcount50 can be used as an independent single channel
counter but to enhance flexibility several USBcount50s can be
stacked together to make a combined 2,3 or 4-channel device. In
this case, each counter is synchronised with the others so that the
compound device acts like a single multi-channel instrument. Each
USBcount50 still needs its own USB connection and the combined
device shares a common ground between all the BNC connectors i.e.
the channels are isolated from the USB but not from each other.
Elan Digital Systems Ltd. 6 USBcount50 USER’S GUIDE Iss1