This DB9 to 3-pin adapter cable is the same cable included with the 2-Channel RS232 Pico module. Whilst we\’ve stocked this to allow owners of the 2-channel RS232 Pico module to purchase a second cable for use with the additional channel, it\’s also useful for any other RS232 projects requiring a breakout to female jumper headers for use with standard 2.54 pin headers. Pinout Black wire = GND Red wire = RX1 Yellow wire = TX1