Glossary · Telephony & India rules
What is DND and the NCPR in India?
DND and the NCPR (India)
DND, short for Do Not Disturb, is the preference a mobile user in India registers with their telecom operator to block promotional calls and messages. It began as the National Customer Preference Register (NCPR); under TRAI's current rules the preferences sit on the operators' shared DLT platform.
On a call
A customer once sent "BLOCK PROMO" to 1909. A campaign pitching them a new credit card is promotional, so calling them breaks their preference. A call about the delivery of something they ordered is a service call, and DND doesn't block it.
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Explained
Here is how it works, in plain words.
Most people in India have been told to “put your number on DND” at some point. It’s one of the few consumer protections everybody knows by name.
Registering is easy. A customer can SMS or call 1909, dial a USSD code, or use the TRAI DND app or their operator’s app. They can block all promotional calls and messages, or only some categories. TRAI lists eight: banking and finance, real estate, education, health, consumer goods and automobiles, communication and entertainment, tourism, and food and beverages. They can also block by mode, such as robo calls, by time band, and by day of the week.
Some hours are quiet by default. Under TRAI’s rules, promotional communication is switched off from 9 pm to 10 am for every customer, unless they choose to switch those hours on.
DND covers promotional communication. Service calls about something the customer already bought, and transactional calls right after they did something, like an OTP, get through. So do government calls in the public interest. TRAI’s 2025 amendment closes the obvious loophole: put a pitch inside a service call and the whole call counts as promotional.
Consent can also open the door. If a customer gives explicit digital consent through the registered process, promotional calls from that sender reach them whatever their DND setting says.
The duty sits with the business making the calls. Scrub the list before every campaign, because people register between campaigns. Keep the consent records. And log every “मुझे call मत करना” so that number never hears from you again.
This is a summary, not legal advice. TRAI’s own text is linked below.
In Voice Infra
This is what Voice Infra does about it.
We keep your own do-not-call list: every campaign checks it at dial time, so a number you add mid-campaign is skipped from that moment and never billed. We don't scrub the national DND register for you, so scrub your list before you upload it.
Questions
People often ask us these questions.
Can I call a DND number for a delivery update?
TRAI's rules treat a call about the delivery of something the customer bought as a service call, and a BLOCK PROMO preference doesn't stop service calls. Keep promotional content out of it, though: a call that mixes in a pitch counts as promotional.
Does Voice Infra scrub numbers against DND?
No. Our own do-not-call list suppresses numbers on your campaigns, but scrubbing against the national register stays with the business placing the calls.
Still deciding? Ask us.
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