If you have a Polaris H series or P series headset and a Starleaf, Aastra or Polycom soundPoint IP phone, then this can be used as a replacement cord.
This is a QD to RJ headset connection. If you have a different phone or headset, you may need the Plantronics Vista cable CPA211. These cables look identical but have different internal wiring.
To check your phone compatibility and if this is the right cord for your headset, use the Plantronics Compatibility Guide