Call detail record

Call detail record

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A call detail record also known as call data record, is a data record
Record (computer science)
In computer science, a record is an instance of a product of primitive data types called a tuple. In C it is the compound data in a struct. Records are among the simplest data structures. A record is a value that contains other values, typically in fixed number and sequence and typically indexed...

 produced by a telephone exchange
Telephone exchange
In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls...

 or other telecommunications equipment documenting the details of a phone call that passed through the facility or device. It is the automated equivalent of the paper toll tickets that were written and timed by operator
Telephone operator
A telephone operator is either* a person who provides assistance to a telephone caller, usually in the placing of operator assisted telephone calls such as calls from a pay phone, collect calls , calls which are billed to a credit card, station-to-station and person-to-person calls, and certain...

s for long-distance calls in a manual telephone exchange
Telephone switchboard
A switchboard was a device used to connect a group of telephones manually to one another or to an outside connection, within and between telephone exchanges or private branch exchanges . The user was typically known as an operator...



A CDR is composed of fields
Field (computer science)
In computer science, data that has several parts can be divided into fields. Relational databases arrange data as sets of database records, also called rows. Each record consists of several fields; the fields of all records form the columns....

 that describe the exchange. Examples of fields include:
  • the number making the call (calling party
    Calling party
    The calling party is a person who initiates a telephone call over the public switched telephone network, usually by dialing a telephone number....

  • the number receiving the call (called party
    Called party
    The called party is a person who answers a telephone call. The person who initiates a telephone call is the calling party....

  • when the call started (date and time)
  • how long the call was (duration)
  • the phone number charged for the call
  • the identifier of the telephone exchange writing the record
  • a sequence number
    Serial number
    A serial number is a unique number assigned for identification which varies from its successor or predecessor by a fixed discrete integer value...

     identifying the record
  • additional digits on the called number used to route or charge the call
  • the result of the call (whether it was answered, busy etc)
  • the route by which the call entered the exchange
  • the route by which the call left the exchange
  • call type (voice, SMS, etc)
  • any fault condition encountered

Each exchange manufacturer decides which information is emitted on the tickets and how it is formatted. Examples:
  • Send the timestamp
    A timestamp is a sequence of characters, denoting the date or time at which a certain event occurred. A timestamp is the time at which an event is recorded by a computer, not the time of the event itself...

     of the end of call instead of duration
  • Voice-only machines may not send call type
  • Some small PBX does not send the calling party
  • to make all the records correct


CDRs are produced by the charging system of the telephone exchanges. In Nortel
Nortel Networks Corporation, formerly known as Northern Telecom Limited and sometimes known simply as Nortel, was a multinational telecommunications equipment manufacturer headquartered in Mississauga, Ontario, Canada...

 exchanges and in other North American exchanges, the charging system is called Automatic Message Accounting
Automatic Message Accounting
Automatic message accounting provides detail billing for telephone calls. When direct distance dialing was introduced in the US, message registers no longer sufficed for dialed telephone calls...

In an Alcatel
Alcatel Mobile Phones is a brand of mobile handsets. It was established in 2004 as a joint venture between Alcatel-Lucent of France and TCL Communication of China....

 OCB switch, the charging system is software known as TX.


Computer network
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....

s are used for transporting CDRs to a central point for processing,
with X.25
X.25 is an ITU-T standard protocol suite for packet switched wide area network communication. An X.25 WAN consists of packet-switching exchange nodes as the networking hardware, and leased lines, Plain old telephone service connections or ISDN connections as physical links...

 links being widely used worldwide for transporting CDRs.
The CDRs of calls still in progress are held by the sending exchange until the call is completed.


Call accounting
Call accounting
A Call Accounting System is a telecommunications software or hardware application that captures, records, and costs telephone usage events. Internationally call accounting systems may be referred to as call logging systems...

 or call logging
Call logging
Call logging is the process of collecting phone call data, analysing this data, and then reporting on the telephone network's cost, performance, capacity and quality of service . It should not be confused with telephone tapping or call recording...

 software is generally used for retrieving and process CDRs. This system can be called a business support system
Telecommunications billing
Telecommunications billing is the process of adding together rated calls or services for a certain user or group of users, applying discounts and preparing the data for invoicing.Billing is also the name for the entire process of creating an invoice...

 (BSS). In the billing system the price of the call will be calculated.

Besides for billing, CDRs can be used for supporting the operations of the telephone company
Telephone company
A telephone company is a service provider of telecommunications services such as telephony and data communications access. Many were at one time nationalized or state-regulated monopolies...

 by providing information on faulty calls, and measures of the amount of traffic taken along particular routes.

Station messaging detail record

A station messaging detail record (SMDR) is similar to a CDR, but the most important difference is in the usage. CDRs are for telephone company use, and may carry information about the processing of a call. To create actual billable call records, it may be necessary to correlate several CDRs. CDRs may also have a role in internal financial transfers among phone companies


Major Account Billing Exchange Logistical record or MABEL, is a vehicle for the exchange of major account billing data between carriers
Interexchange carrier
An Interexchange Carrier is a U.S. legal and regulatory term for a telecommunications company, commonly called a long-distance telephone company, such as MCI , Sprint and the former AT&T in the United States...

. The records cover all of the billing elements of a major account, including summary billing information and call detail-level information.

A wireless service provider or a company that acts as a liaison to a wireless service provider uses MABEL. Also defined in MABEL is a Major Account Consolidator, which can be the wireless service provider or third party that acts as a liaison to the corporate entity. MABEL

SMDR, in contrast, is intended for end-user
Economics and commerce define an end user as the person who uses a product. The end user or consumer may differ from the person who purchases the product...

 organization, and as a way to understand their telephone usage and billing.

See also

  • Customer proprietary network information
    Customer Proprietary Network Information
    Customer proprietary network information is the data collected by telecommunications companies about a consumer's telephone calls. It includes the time, date, duration and destination number of each call, the type of network a consumer subscribes to, and any other information that appears on the...

  • NSA call database
    NSA call database
    The United States' National Security Agency maintains a database containing hundreds of billions of records of telephone calls made by U.S...

  • Telecommunications data retention
    Telecommunications data retention
    In the field of telecommunications, data retention generally refers to the storage of call detail records of telephony and internet traffic and transaction data by governments and commercial organisations...

  • Pen register
    Pen register
    A pen register is an electronic device that records all numbers called from a particular telephone line. The term has come to include any device or program that performs similar functions to an original pen register, including programs monitoring Internet communications.The United States statutes...

  • Internet Protocol Detail Record
  • Communications data
    Communications data
    Communications data concerns information about communication.Communications data is a part of a message that should be distinguished from the content of the message...

  • Datacom
    Datacom can refer to:* Data communications* DATACOM/DB, a relational database for IBM mainframes sold by Computer Associates...

  • Average call duration
    Average call duration
    In telecommunications, average call duration is a measure based on a call record sample to determine traffic demand and forecast call volumes, serving also as a tool for infrastructure monitoring ....

  • Answer/seizure ratio

External links