The VoiceStation, like all our analog phones, is not a VoIP phone so it does not use PoE.
The cable does look like a Cat 5 cable but has an additional noose on the side to prevent someone plugging it into a RJ45 Ethernet port and potentially causing damage to a Ethernet port.
You can in theory replace it with a Cat 5 cable at your own risk.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Polycom Global Services
Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels. Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's