The JSB360 USB Watchdog Timer module provides a method to monitor a host computer and program.  It is a fact of life that a computer or program may fail. To reduce the risk and possible damage a failure can cause, there is two possible methods (1) redundancy (2) watchdog timer. Neither method offer 100% protection, but both reduce risk or consequences of failure. Redundancy, a duplication of hardware is very expensive. On the other hand the JSB360 offers excellent protection at a very low cost.  The host computer or application must communicate with JSB360 in one of two methods within prescribed programmable time intervals. Communication method one the host computer sends a USB message to the JSB360.  The other methods the host computer generates a hardware pulse to an dedicated opto isolated input on the JSB360.  If the communication does not occur within that programmed time frame, the JSB360 will trigger a relay closure and drive a darlington driver output on.  These event can be used to trigger a system reset and or a warning device. There are 3 relays that change states when a time-out occurs. 1 relay is meant to be closed by the user application before WDT is starts, and this relay will open on time-out, the second relay will close when the time-out occurs and will only remain closed for the time-out value, then open again (used a reset pulse). The third relay closes on time-out and remains closed until a reset is performed.