LG Wireless Phone

How do cell phones tell time?

Let's say I have a Verizon cell phone, my friend has a Sprint cell phone, and my other friend has a Cingular cell phone. We all have the same area code. Is there a way to know if the three phones will tell the same time without actually putting them side-by-side and comparing them? Do cell phones use a cell tower to get their time? What do cell towers use? Do the various major carriers all use the same source to set their clocks? Thank you for the answer re: networks recording when calls are made. Do all networks (e.g., Verizon and Cingular) synchronize off the same time source? Is this something regulated by the Government?

Public Comments

1. Usually, the clock in the phone does not get the time from the network. It's more like a digital watch. Internally in the network, the messaging between exchanges needs very accurate time. All exchanges are synchronised to a common time source such as an atomic clock. The network elements that for example create a billing record are accurate to a few milliseconds.