A detonation system for use with supply of electrical energy has user operable firing console for selectably transmitting unit identification information, firing delay time information and selections from a command set including Output, Delay, Fire (Time), Abort, Power Up (Arm), Input, and Store. The console displays responses or information digested from responses by electrical delay detonators to the commands. The detonators have explosive, a capacitor for storing energy from the supply to set off the explosive, circuitry for charging the capacitor from the supply and transferring the energy from the capacitor to the explosive in response to first and second signals generated in response to the commands. Each detonator can be programmed with a unique identification number and delay time. The time base in each detonator can be compensated so that errors in the time base are obviated so as to achieve the correct delay. Security code circuitry and software are described so that each detonator can only be set off by authorized users.