DLT registration is the process of listing your business, sender ID (called a Header), and every message or call template on a TRAI-regulated Distributed Ledger Technology platform before you're allowed to send bulk commercial SMS or run outbound calling campaigns to Indian mobile numbers. It's a one-time entity registration, followed by an approval step for each new template you want to use.
If you've ever wondered why a business texting or calling you shows a recognisable, verified sender ID instead of a random 10-digit mobile number, DLT is the system behind that. Here's what it actually involves, in plain English.
What DLT registration actually means
DLT stands for Distributed Ledger Technology — a blockchain-based record that India's telecom operators (Airtel, Jio, Vodafone Idea, BSNL) jointly maintain under rules set by TRAI, the Telecom Regulatory Authority of India. The framework itself is called TCCCPR (Telecom Commercial Communications Customer Preference Regulation), introduced in 2018. Registering on any one operator's TRAI-approved DLT platform is recognised across all networks — you don't need to register separately with each telecom operator.
- Principal Entity: the business sending the communication — this is the role most companies register under
- Header: the sender ID customers see (a short code or business name), registered against the Principal Entity
- Template: the exact wording of each message or call script, pre-approved before it can go live
- Telemarketer: a separately licensed role for aggregators and agencies that send bulk communication on behalf of multiple businesses
Why TRAI requires it
DLT exists to make commercial SMS and calling traceable back to a real, registered business, and to give TRAI and telecom operators a way to enforce India's Do Not Disturb (DND/NDNC) rules automatically. Before DLT, spam and fraud calls using spoofed or unregistered numbers were difficult to trace or block at the network level. Registered, template-approved traffic is easier for operators to verify and deliver reliably; unregistered traffic is the first thing that gets filtered or blocked.
Who actually needs to register
Any business or organisation sending bulk promotional, transactional, or service SMS, or running commercial outbound voice calling campaigns, to Indian phone numbers needs to register as a Principal Entity. In practice this covers banks and NBFCs sending payment reminders, ed-tech and coaching institutes calling leads, real estate and recruitment agencies running outbound campaigns, D2C and e-commerce businesses confirming orders, and any company using an AI voice agent or dialer for outbound calling in India.
How to register: step by step
- 01Pick a DLT platform operated by any major telecom operator (Airtel, Jio, Vodafone Idea, and BSNL each run one) — registration on one is valid across all networks.
- 02Register your business as a Principal Entity using company documents (CIN or GST registration, PAN, and authorised signatory details).
- 03Register your Header(s) — the sender ID your customers will see on SMS or verified calls.
- 04Submit each message or call script as a Template and wait for approval before using it live.
- 05Once approved, only send or call using registered Header + Template combinations — anything else risks being blocked by the operator.
Headers and template types
| Type | Format | Typical use |
|---|---|---|
| Promotional Header | 6-digit numeric code (first digit maps to industry) | Marketing, offers, telemarketing calls and SMS |
| Transactional / Service Header | 6-character alphabetic code | OTPs, order confirmations, appointment reminders, service alerts |
| Government / Transactional | 6-character alphabetic code, government-issued | Communication from government bodies and PSUs |
For outbound voice calling specifically, the Header registration also connects to TRAI's separate number-series rules — the 140-series for promotional calls and the 160-series for verified BFSI and government service calls. If you're getting calls from one of these and want to understand what they mean, see our explainer below.
What happens if you skip it
- Telecom operators increasingly block or heavily throttle bulk SMS and outbound calling traffic from unregistered senders, often without warning
- Calls or messages to numbers on the National DND registry sent without proper registration and consent basis carry regulatory risk under TCCCPR
- Unregistered traffic is harder to trace, which is exactly the pattern spam-filtering systems are built to catch and deprioritise first
- Fixing a compliance gap after a campaign has already launched costs more time than registering correctly before you start
DLT rules for AI voice calling
Everything above applies whether your outbound calling is done by a human dialer team or an AI voice agent — DLT registration is entity-specific, not tool-specific. If you're specifically evaluating an AI calling platform for India, we've written a deeper breakdown of how DLT registration and DND scrubbing apply to AI voice agent campaigns, including who's responsible for what between your business and your vendor.
How DLT registration and DND scrubbing apply specifically to AI voice agent outbound calling, and what Vaami supports out of the box.
See how DLT-aware outbound calling looks in practice for high-volume candidate screening campaigns.
Vaami's Hindi-language AI calling agent for Indian businesses — pricing, setup and language coverage.