| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To easily switch possible/impossible of data writing to a ROM built in an optical module from an external system equipment side by adding a circuit consisting of a gate element (inverter) and a resistor in the optical module. <P>SOLUTION: The optical module 10 is connectable with a system equipment 20 and has a gate circuit 4 consisting of an EEPROM 3b for storing the data, a writing protection terminal WP, the gate element 4b and the resistor 4a for setting writable/unwritable of data to the EEPROM 3b. The gate circuit 4 outputs "High" to the WP in the case that an input level from the system equipment 20 is "Low" and outputs "Low" to the WP in the case that the input level from the system equipment 20 is "High". The EEPROM 3b becomes to be unwritable when "High" is output to the WP and becomes to be writable when "Low" is output to the WP. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
