This is a 520nm 1W fiber coupled laser module. There are CW and TTL working mode. When CW working mode is required. Red and Yellow wire to DC 12V positive. Black and Green wire to DC 12V negative. When TTL working mode is required. Red wire to DC 12Vpositive. Black wire to DC 12V negative. Yellow wire to 0~5V Signal positive. Green wire to 0~5V Signal negative. The TTL Signal is Square wave, 0~5V and 1~10kHz. Adjust the signal frequency to test the TTL function. Let’s check it now.