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This modular adapter has a DB25 Female connector that plugs into DB25 RS232 serial port and converts it to an RJ11 or RJ12 connection. RJ12 Pinout: Pin1 -- White Pin2 -- Black Pin3 -- Red Pin4 -- Green Pin5 -- Yellow Pin6 -- Blue. Gold plated pin. 28AWG wire. Molded Gray color housing. Thumb screw.