Mobile phones and pen/paper are not good for PCI compliance
Mobile phones and pen/paper are not good for PCI compliance. A lot of centres now have portable white boards for advisors so that they can write down customer details and wipe them off at the end of the call/ end of the shift. This ensures that customer details do not leave the building.
A number of centres provide lockers outside the main floor so that phones can be left securely.
The other approach is to use an automated payment system (either online or IVR) to ensure that members of staff never come in contact with credit card details.