It’s the IP address of the device, not the area code.
It doesn’t identify the person, just the device and the location where it was originally set up.
Anyway if you see the same IP address at multiple locations, you pretty much know it’s the same person. People don’t lend their phones to other people very often.
“It’s the IP address of the device”
“Anyway if you see the same IP address at multiple locations”
IP address for a phone is not fixed but depends on which data provider you are connected to.
For example my phone’s IP address is currently the same as my laptops IP address because they are both connected to our home wifi.
But if I switch off wifi on the phone or travel outside, the IP address will change and will depend on what cell phone tower it is connected to.