Call Detail Records

What are Call Detail Records? Call Detail Records are the technical information mobile phone operators record from a cell phone as it moves around. For a cell phone to make a call, send or recieve a text message, or use an App (Facebook, Twitter, Instagram, etc.), the phone must be connected to a cellular tower. The approximate location of the phone and what it is transmitting an receiving (voice, data, SMS) comprise the majority of the CDR data cell phone companies collect and store.

This article on Wikipedia goes into great deal of detail explaining CDR data.

Call Detail Records (CDR)

From Phone Carrier Companies (AT&T, Verizon, etc). The best information may be with the carrier, not necessarily the phone CDR’s contain a wealth of information.

Call Detail Record Requests

  • Must be requested from the individuals account if you have access to it
  • By subpoena from law enforcement, if involved
  • By request if you file civil action/lawsuit

Data Provided by CDR Analysis

  • Date, time and phone number of calls or texts (but not not content)
  • Duration of call
  • Voicemail numbers
  • Cell tower location the phone was connected to when the call was made (geo location)
  • Possibly the Tower Antenna used (direction from the tower)

Carriers also retain more accurate location data for a limited time called: RTT, NELOS, etc. Some carriers only record tower details for calls, others for calls and texts. AT&T is a goldmine – AT&T retains quite a bit of data and retains it for a lengthy period. Smaller cell phone operators tend to record less and retain it for shorter periods of time.


“When wife’s killer found out she was dead (he was only one that knew at the time) he proceeded to drive west from Salt Lake City UT down I-80 to the town of West Wendover, NV.
On the way there, his phone contacted several therapists at a specific date and time. I can tell you where he was on I-80 to within a few hundred meters.
He spent less than 3 hours in West Wendover (presumably to dispose of evidence) and then returned. By doing that he created more evidence.”

Translate »