Color:DB9 Male To DC 3.5mm Cable
6feet DB9 Male To 3.5mm Serial Cable
DB9Pin Serial Transfer Cable For Devices
Stereo 3.5 mm Jack To DB9 Pin Male Serial Port.
Primarily used to transfer Serial Data back and forth from Small devices.

Wiring Schematic:
DB9 TRS Connector / Audio DC3.5mm
Pin 1-6-7-8 open
Pin 2 Tip - Left
Pin 3 Ring - Right
Pin 4 open
Pin 5 Shield - Ground
Pin 9 open
Connector 1: DB9Pin Male ;Connector 2: DC3.5mm Male
Adapt Your 3.5mm stereo Jack For RS-232 Serial Control
This Adapter Is Ideal For Use With Computers, Projectors, And Any Control Unit&Display Requiring 3-Conductor RS-232 Serial Control
The Velocity RS-232 Adapter Leverages Your DB9 Or 3.5mm Stereo Audio Cable To Run 3-conductor RS-232 Control Signals Between Your Control Unit And Your Video Display.Fully Molded DB9 And 3.5mm Connectors Provide Excellent Strain Relief