Because the phone relies on standard analog telephony infrastructure, basic setup and troubleshooting align closely with standard Panasonic Operating Instructions . Hardwired Installation
To find the exact user manual for your device, you can use the official Panasonic Manual Search Portal . panasonic kxtsc934cid user manual link
Or, you can visit the Panasonic support website and search for the model number "KX-TSC934CID" to access the user manual. Because the phone relies on standard analog telephony
This is not a phone error. Your telephone provider is not sending the CID data. The manual explains how to check your subscription and run a "CID Service" test mode on the phone itself. panasonic kxtsc934cid user manual link