Detector detecting transmission performance of optical composite cable

A detector detecting transmission performance of optical composite cable which comprises optical fibers and electric lines, comprising:

• a first unit which is connected to a connector formed at one end of said optical composite cable and comprises a optical loop part connecting a first optical fiber and a second optical fiber and a short-circuit part which short-circuits plural electric lines in said optical composite cable;
• and
• a second unit comprising a transmission loss measuring part, which is connected to a connector formed at the other end of said optical composite cable and measures transmission loss between ends of said first optical fiber and said second optical fiber returned by said optical loop unit, a resistivity measuring part, which measures resistivity between ends of electric lines returned by said short-circuit part, a disconnection detecting part, which detects connection or disconnection of electric lines by using measured resistivity, and a display part, which displays the result of transmission loss measured by said transmission loss measuring part and connection or disconnection detected by said disconnection detecting part.