Electronic device

An electronic device comprising:

• a mounting section that accepts a removable, externally-connected device and connects to a data line into which a unit signal having a data period for transmitting a data signal and a detection period for transmitting a detection signal is fed from the externally-connected device;
• a voltage determiner that determines an electric potential of the data line so as to have a first logical value when the externally-connected device is detached from the mounting section;
• and
• an attach-detach detector that detects whether the externally-connected device is mounted on, or detached from the mounting section,
• wherein, the attach-detach detector detects whether the externally-connected device is mounted on, or detached from the mounting section by detecting the detection signal of the unit signal having either the first logical value determined by the voltage determiner or a second logical value.