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November 3, 2026 · By Piyush Sahoo CDR stands for call detail record. It is the structured entry a telephone network or voice platform writes for a call, listing the numbers, timestamps, duration, outcome, and often cost and quality. It holds no audio. Outside telecom, CDR can also mean corporate debt restructuring or crude death rate. This guide reads one call field by field, shows which record answers which question, and sets out India’s retention and access rules, each linked to its source.
Key takeaways
  • A CDR is metadata, not content. It says who, when, how long, and how it ended, and never what was said.
  • duration and billsec measure different things. Ring time counts toward the first and not the second, so check charges against billable seconds.
  • In India, retention depends on who holds the record. Telecom operators keep CDRs for two years, and call centres under DoT’s 2021 guidelines for one.
  • Your business’s CDRs and an operator’s subscriber CDRs are different things. You can export your own platform data, while operator records generally move only through police or court channels.
  • Your CDRs can approximate TRAI’s spam signals. You can count call volume, recipient diversity, average duration, and the incoming-to-outgoing ratio from your own rows.

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What does CDR stand for?

In telecom and in police work, CDR means call detail record. The idea has a paper ancestor: Wikipedia describes the CDR as the automated equivalent of the operator’s toll ticket. Search for “CDR full form” and you also find unrelated meanings, so check the context first. The rest of this guide covers the telecom meaning. You may also meet some close relatives: some PBX vendors say SMDR, for station messaging detail record, and DoT’s guidelines add UDR, for usage data record.

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What does a CDR contain?

A CDR is one row per call, or per call leg on many platforms. No single global format sets its fields, so names vary by vendor, but the same six families appear almost everywhere. Diagram of one CDR row split into six field families: who, when, outcome, money, route and quality, with a dashed box noting that audio and transcripts are not in the row. Diagram of one CDR row split into six field families: who, when, outcome, money, route and quality, with a dashed box noting that audio and transcripts are not in the row. If you’ve moved between systems, this translation table saves time. The classic terms come from Wikipedia and KrispCall, the SIP platform names from DIDLogic, and the last column from the Vobiz CDR object. Cause values have their own lineage. ITU-T Q.850 defines the cause information used in ISDN and SS7 signalling, and many telephony systems report a form of it, with cause 16 meaning a normal clearing. Quality scores such as MOS use a scale that typically runs from 1 to 5, with terminology defined in ITU-T P.800.1.

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Metadata is not harmless

Exotel’s glossary argues that CDRs carry a lighter privacy burden than recordings because they hold no conversation. That’s fair as a comparison, but DIDLogic rightly warns against treating exports as low-risk logs. Contact patterns alone can be revealing. An operator’s CDR can include a cell ID that points to a tower sector, and the Internet Freedom Foundation calls this data sensitive. Give your CDR exports the same access controls as other customer data.

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Reading one call, field by field

The fields make more sense laid over a call. In this example, the phone rang for 7 seconds and the conversation lasted 184. Timeline of one answered call showing ring_time of 7 seconds, billsec of 184 seconds and duration of 191 seconds, then an unanswered call with billsec of 0 and an empty answer_time. Timeline of one answered call showing ring_time of 7 seconds, billsec of 184 seconds and duration of 191 seconds, then an unanswered call with billsec of 0 and an empty answer_time. Here is the same call as a reader would interpret it. Every value is illustrative, and the numbers are masked. DIDLogic’s list of common mistakes includes two that hit reporting hardest:
  • Summing duration to check talk-time charges. That sum includes ringing, so it overstates billable time. On Vobiz, billsec holds talk time only.
  • Counting one conversation as one row. A bridged call has more than one leg, and each can be rated separately. Link related rows with an identifier such as bridge_uuid, the UUID of the bridged leg, before you count conversations.

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Which call record answers your question?

Teams often query the wrong record for their question. Each one answers something different, and they work best together. Decision map linking five questions to records: cost and parties to the CDR, spoken content to a call recording, live events to webhooks, failures to a SIP log plus CDR quality fields, and internet use to an IPDR. Decision map linking five questions to records: cost and parties to the CDR, spoken content to a call recording, live events to webhooks, failures to a SIP log plus CDR quality fields, and internet use to an IPDR. Don’t assume operator CDRs are instant, either. One stakeholder told TRAI that operator CDRs reach the database only after 24 to 36 hours, and TRAI’s analysis accepted that same-day CDR analysis wasn’t possible. Platform timing differs by provider, so confirm yours before you build alerts on it.

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What can you do with call detail records?

Competing guides list the same headline uses: billing, reporting, and fraud detection. Here is how each works in practice.

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Reconcile the bill

Export a month of CDRs, sum billable seconds and cost by route or number, and compare the totals with your invoice. Rows that disagree point to rating questions, such as a pulse or a route you didn’t expect. Your rate card decides how seconds become money, so apply its rules before you call something an error.

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Find out why calls fail

Work through a problem call in a fixed order: was it answered, did media flow, and how was the quality? Flow chart for a problem call. Without an answer_time, read hangup_cause to separate the callee, bad data and network problems. With an answer_time, check for MEDIA_TIMEOUT, then for low MOS, high jitter or packet loss. Flow chart for a problem call. Without an answer_time, read hangup_cause to separate the callee, bad data and network problems. With an answer_time, check for MEDIA_TIMEOUT, then for low MOS, high jitter or packet loss. The causes come from Vobiz’s CDR reference and hangup cause list. A single row rarely proves much. Group by destination prefix, trunk, or hour, because a failure that clusters tells you where to look.

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Spot fraud early

Unusual patterns tend to show up in the CDR before anywhere else, such as a spike in international traffic. Compare today’s traffic with your usual baseline for destinations, hours, and short-call volume, and alert on large jumps. Vobiz’s dashboard guidance gives one example: a sudden cluster in a country you don’t serve calls for a CDR cross-check.

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Check your calling against TRAI’s spam signals

No ranking guide we read covers this one, and it matters to Indian senders. TRAI’s February 2025 amendment tells operators to treat senders as suspected unregistered telemarketers based on signals, and your own CDRs can approximate each one. The regulation leaves the thresholds to TRAI, and the text we read doesn’t state numbers, so use these as trends and not as a pass mark. The September 2026 Third Amendment goes further, with AI-based flagging of high-probability spam numbers on behavioural parameters. It also gives senders a way to contest a flag, and it says numbers in dedicated commercial series aren’t to be flagged as suspected spam. Its provisions start 30 to 90 days after Gazette publication, so check which ones are live. Our India calling regulations page covers the wider rules. CDRs also decide complaints. The Third Amendment’s memorandum reports that, from January to April 2026, 1,32,137 of 12,37,707 complaints (10.68%) were declared invalid because the CDR did not match. TRAI responded by adding the power to call for CDRs when it audits complaint handling.

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How long must CDRs be kept in India?

The answer depends on who holds the record. A government direction, a dispute, or a legal hold can extend these periods. The DPDP row also requires erasure afterwards unless another law requires longer retention. Bar chart of retention periods in India: telecom operator CDRs 24 months, operator complaint records 24 months, OSP CDRs 12 months, enterprise communication service user records 12 months, and DPDP traffic data and logs 12 months from May 2027. Bar chart of retention periods in India: telecom operator CDRs 24 months, operator complaint records 24 months, OSP CDRs 12 months, enterprise communication service user records 12 months, and DPDP traffic data and logs 12 months from May 2027. Four details are easy to miss: This section is a map, not legal advice. As of 3 November 2026, we found no DoT text replacing the 2021 OSP guidelines, but we couldn’t confirm how the 2026 authorisation rules treat them. Ask counsel which category you fall into.

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Who can get a CDR in India?

The answer depends on which CDR you mean, because two very different records share the name. For operator records, the position is narrower than many people expect: If a CDR goes to court, getting the record is only half the work. Section 63 of the Bharatiya Sakshya Adhiniyam replaced Section 65B of the Evidence Act from 1 July 2024, and a certificate must accompany the output. Take advice from your lawyer on what yours should say.

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How Vobiz handles call detail records

Vobiz writes a record for each call and exposes it through the API and the Console. Reading CDRs doesn’t place calls. You need your own Auth ID and Auth Token for API access.
  • Query. The list endpoint filters by number, date range, direction, minimum duration, sip_call_id, bridge_uuid, hangup_cause, hangup_disposition, context, and campaign_id, plus free-text search. It also returns a summary with total calls, answered calls, answer rate, billable seconds, and total cost.
  • Look up one call. Fetch a single CDR by call ID, for example one you got from a webhook. Use the recent endpoint for the latest calls with no date range.
  • Export. The CSV export returns one row per call for the filters you set, ready for reconciliation or your own data store.
  • Browse. The Console has voice call logs, SIP call logs, and campaign call logs, with call timing and hangup causes. Voice and SIP logs also show MOS.
  • Resell. Partners can read per-customer CDRs across their accounts, and CDRs for inbound calls to numbers assigned to a sub-account belong to that child account.
For real-time logic, pair CDRs with the Hangup event from webhooks (callbacks), which is the authoritative end-of-call signal. On conference legs, read hangup_source alongside ConferenceExit callbacks when you need exact attribution.

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Frequently asked questions

CDR stands for call detail record. It is the structured entry a network or voice platform writes for a call, with the numbers, times, duration, and outcome. Mobile core networks also use CDR for charging data record, a billing record defined by 3GPP.
It is the same term: call detail record. Investigators use an operator’s CDR to see which numbers were in contact, when, and for how long. A cell ID in the record gives only an approximate location, because it identifies the tower sector and not an address.
No. A CDR is metadata about the call and holds no audio or transcript. A recording is a separate file that exists only if someone turned recording on. Many systems link the two through a shared call identifier, so you can move from a row to its audio.
Telecom operators must keep CDRs for two years, under the Unified Licence and Rule 45(2) of the 2026 Principal Services Rules. The government can direct a longer period. DoT’s 2021 guidelines give call centres and other OSPs a one-year period. Check current text and take legal advice.
Usually not by simply asking. Indian lawyers and court summaries describe operators releasing CDRs only to law enforcement or against a court order, including a summons under Section 94 BNSS. For everyday needs, ask your operator for an itemised bill or usage statement instead.
A CDR describes a phone call: the parties, times, and outcome. An IPDR, or IP detail record, describes a subscriber’s internet use. Indian telecom operators must retain both for two years, along with exchange detail records, under the same licence condition.

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Further reading on Vobiz

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Sources

Indian regulators and government Legal commentary and reporting Standards Industry guides Reference

Query your call records on Vobiz

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