| 摘要 |
<p>PROBLEM TO BE SOLVED: To facilitate a countermeasure for two kinds of communication standards for a single connector, and to cause normal operation of electronic equipment, regardless of the relation between a power supply voltage and a signal voltage. SOLUTION: A polarity detecting means 1b detects the polarity of a power supply voltage supplied from signal lines 2b and 2c of a connection cable 2. A polarity-inverting means 1c inverts the polarity of the power supply voltage supplied from the connection cable 2, according to the polarity of the power supply voltage detected by the polarity detecting means 1b. A first communication control part 1g is based on the first communication standard. A second communication controlling part 1h is based on the second communication specification. A selecting means 1d selects one of the first and second communication control parts, and connects the selected communication control part to the signal line 2d and 2e of the connection cable 2. A control means 1e insulted electrically from the selecting means 1d, and the selecting means 1d is controlled, according to the detected result of the polarity of the polarity detecting means 1b.</p> |
