The Main Unit I is the ideal solution to many individual switching & control tasks. The unit is based on a MC 68HC05B6 microcontroller with 8 A/D converter inputs. The 16 digital connections are programmable & can be used as inputs or outputs. For analog signals you are provided with 8 inputs & 2 pulse width modulated outputs. The 8 k B EEPROM memory holds the user program which you have written & can also record results or measurements. 256 bytes are also available for you to use for assembly code. The 9 pin serial interface connects the Main Unit I with your PC. As programming software you may choose between the Plus version which provides a graphical solution or the Basic version which provides line text. The saved data remains available even after a power failure because of the use of EEPROM storage. If you want to use your Main Unit I to switch, adjust or control accurately to the second, simply connect an external DCF-77 antenna. Two buttons are provided on the circuit board & these enable you to start the program or reset the system. & for energy saving st&-alone operation, you may use jumpers to separate the interface components & the LEDs from the operating voltage.