Under the black cover, there are eight switches.These switches can be used to simulate fault conditions in various parts of the circuit. The faults are normally used one at a time, but remain safe under any conditions of use. To ensure that the ANACOM 1 boards are fully operational, all switches should be set to OFF. Access to the switches is by use of the key provided.Insert the key and turn counter-clockwise.To replace the cover,turn the key fully clockwise and then slightly counter-clockwise to release the key