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CDR Logging

Call Detail Records (CDR) log telephony events including phone calls, SMS messages (CDR version only), and cellular LAC/TAC changes. CDR logging provides a timeline of communication events with associated network information.

What are CDRs?

Section titled “What are CDRs?”

Call Detail Records are event logs that capture:

  • Phone calls (incoming, outgoing, missed)
  • SMS messages (CDR version only)
  • Tower changes (LAC/TAC cell changes)
  • Timestamp and location for each event

CDRs are separate from continuous cellular surveys - they log specific events rather than periodic scans.

Version Differences

Section titled “Version Differences”

CDR logging varies between app versions due to Google Play restrictions:

FeatureRegular (Play Store)CDR (F-Droid/GitHub)
Call Events✅ Yes✅ Yes
SMS Events❌ No✅ Yes
Phone Numbers❌ No✅ Yes
LAC/TAC Changes✅ Yes✅ Yes

See Build Variants for why these differences exist.

Events Logged

Section titled “Events Logged”

Call Events

Section titled “Call Events”

Event Types:

  • Incoming Call - Received call
  • Outgoing Call - Placed call
  • Missed Call - Unanswered incoming call

Data Captured:

  • Call direction (incoming/outgoing)
  • Duration (if answered)
  • Timestamp
  • Serving cell information at time of event
  • Location (if GPS available)
  • Phone number (CDR version only)

SMS Events (CDR Version Only)

Section titled “SMS Events (CDR Version Only)”

Event Types:

  • Incoming SMS - Received text message
  • Outgoing SMS - Sent text message

Data Captured:

  • Message direction
  • Timestamp
  • Serving cell information
  • Location (if GPS available)
  • Phone number (CDR version only)

LAC/TAC Change Events

Section titled “LAC/TAC Change Events”

When Logged:

  • TAC/LAC changes

Data Captured:

  • New cell information
  • Timestamp
  • Location

CDR CSV Structure

Section titled “CDR CSV Structure”
# Created by Network Survey version=1.42-cdr
# CSV Version=0.2.0
startTime,latitude,longitude,altitude,accuracy,event,originatingAddress,destinationAddress,csAccessNetworkTechnology,csCellIdentifier,psAccessNetworkTechnology,psCellIdentifier,slot,locationAge
2025-09-15T10:30:54.748812-04:00,37.7749,-122.4194,184.3000030517578,17.596,LOCATION_UPDATE,,,NR,310-260-1234567-1234567890,NR,310-260-1234567-1234567890,,5813
2025-09-15T10:31:13.060772-04:00,37.7750,-122.4195,184.60000610351562,36.735,LOCATION_UPDATE,,,LTE,310-260-12345-12345678,LTE,310-260-12345-12345678,,3572

Use Cases

Section titled “Use Cases”

Network Monitoring

Section titled “Network Monitoring”
  • Track when tac/lac changes occur
  • Identify problematic areas (frequent handovers)
  • Monitor network registration events

Privacy Auditing

Section titled “Privacy Auditing”
  • Review what network events occur
  • See which towers handle calls/SMS
  • Understand network behavior during communications

Research

Section titled “Research”
  • Correlate network events with location

Enabling CDR Logging

Section titled “Enabling CDR Logging”

From Dashboard

Section titled “From Dashboard”
  1. Open Network Survey
  2. Find “CDR” card (if available in your version)
  3. Toggle CDR logging “On”
  4. Grant phone state and/or SMS permissions if prompted

See Required Permissions for details.

Section titled “Related”