Is Witness PCI-Compliant?

Yes.

Witness provides end-users with the ability to silence recordings during any dialogue which might contain sensitive information (e.g. credit card details). This is achieved via Start-Silence and Stop-Silence instructions which can be sent via a user’s telephone handset (DTMF tones). If integrating Witness with another system (e.g. CRM), these instructions can also be called via Witness’ API.