Compact electronic apparatus with units each having independent housing for circuit board and functional devices

A small-size electronic apparatus having a combination of a plurality of units each comprising a circuit board and various functional components housed independently in said units on a function to function basis, each of said units further comprising:

• a unit frame in which said circuit board and said functional components are mounted, and which has a connector for electrically being connected to a circuit board and functional components of other units in a direction of connection to said other units;
• a front panel which has a first and a second fit coupling means, said front panel being connected to and removed from said unit frame by said first fit coupling means;
• and
• a housing which receives said unit frame, and which has a guide rail means for interconnecting said housing with said unit frame and a unit connection surface having a locking means for interconnecting and locking said units together, such that, by causing said housing to slide along said guide rail means toward said front panel, said housing is secured to said unit frame and said front panel by said second fit coupling means, and also housings of said plurality of units are interconnected and locked.