DLT registration for SMS: steps, fees, sender ID and templates, with real estate examples and fixes when OTPs don't arrive

DLT registration is what a business has to complete before Indian telecom operators will deliver its commercial SMS. You register once as a principal entity on any operator's DLT portal, then add your sender IDs (headers), your message templates and, if you need explicit consent, consent templates, and bind the telemarketer chain your SMS provider uses. Every SMS is checked against all of this before delivery. If it fails even one check it gets dropped, and that is how an OTP or a site-visit reminder leaves your system and never reaches the buyer.

This guide is for the builder's marketing or IT person, or the CP firm owner, whose SMS are not arriving. It ends with a fix for each failure.

What DLT registration is, and why it exists

The rules are TRAI's Telecom Commercial Communications Customer Preference Regulations, 2018, notified on 19/07/2018 to curb unsolicited commercial communication. They put every sender, header, template, consent and customer preference on distributed ledgers that the operators run and share. The Saudaflow glossary has a one-paragraph definition for colleagues.

Real estate is clearly covered. A project promotion sent by SMS is commercial communication, and real estate is one of the eight categories customers can block by name.

TRAI has amended the rules more than once, and this guide follows two of those amendments. The earlier one is the Second Amendment Regulations, 2025, notified on 12/02/2025. The Third Amendment Regulations, 2026 followed, published in the Gazette dated 18/09/2026, and most of it applies 30 days after publication, so it's already in force by the time you read this. Two parts start later. The six-hour suspension of misused headers and templates and the new rules for automated calls start after 60 days, in the second half of November 2026. The one-month suspension for wrongly categorised templates and the new complaint appeals start after 90 days, in December 2026.

Who registers what

In the operators' FAQs, principal entities are the businesses that send commercial messages, and registered telemarketers carry those messages to the operators.

You can't deliver messages yourself, even as a principal entity, because the Vodafone Idea and BSNL DLT FAQs say you must use a telemarketer with the delivery function. And since 2025 there's a limit on how many intermediaries can sit between you and that telemarketer, the idea being that every message can be traced (PIB, 12/02/2025). Registration is per legal entity, which means a builder with a separate company for each project registers every company that sends SMS in its own name.

DLT registration steps for a builder or CP firm

1. Pick one operator's portal. The Vilpower FAQ (Vodafone Idea) and the BSNL DLT FAQ say a principal entity registers only once, and its entity ID works with every operator. Jio's portal is TrueConnect, and Airtel's is its commercial communication platform.
2. Sign up as a principal entity. Pick your type (proprietor, partnership, company, LLP) and put real estate down as the line of business, which sounds obvious, but it matters, because the same FAQs say your messages must match it.
3. Upload documents. That's the business PAN, the authorised person's mobile and email, the business proofs the portal lists, and a letter of authorisation if your SMS provider registers for you. Since 2025 there's more, as registration now also has to include physical verification, biometric authentication and a unique mobile number.
4. Pay the fee. Each operator sets its own. The Vilpower and BSNL FAQs list ₹5,000 for a principal entity, non-refundable, valid for one year with a 30-day grace period, so check the amount, tax and renewal terms on the payment page before your accounts team releases the money.
5. Answer the registrar. By the same FAQs it has 72 working hours to verify your entity once your documents are uploaded and the fee is paid. If it comes back with queries, reply fast, because an account whose queries sit unanswered for 15 working days is deleted.
6. Build on the entity ID. Register headers, content and consent templates, add your telemarketer and confirm the chain, and whitelist every link and number you will send.
7. Keep it alive. Renew the entity registration each year, and keep every header in use, because the FAQs say a header inactive for more than 90 days goes back to the header pool for others to take. Operators can also ask you to re-verify headers and templates; TRAI's direction of 16/02/2023 had them re-verify every registered header (Khaitan & Co's summary). Watch your portal's notices.

SMS header registration: format and types

The header, or sender ID, is the name the buyer sees. On the Vilpower and BSNL portals it has six characters, with no spaces or special characters. Their FAQs show six digits for promotional messages, such as 565690, and six letters for transactional and service messages, such as KLMNOP. Sender ID registration starts once your entity is approved.

• Make it recognisably yours. The FAQs say a header should relate to your business, and restrict celebrity and political names, trademarks, other companies' brands and government or SEBI-related headers. TRAI has also told operators to clear out look-alike headers (letter of 22/03/2024, per Khaitan & Co).
• Headers stay with you. You can't hand a header over to anyone else, though you can surrender it.
• Plan one header per job. Since TRAI's direction of 20/08/2024, a content template may be linked to only one header, so a common set-up is a letter header for OTPs and service messages and a number header for promotions.

Phones also show a two-letter prefix before the header for the sending operator and its service area, so AD means Airtel Delhi (MediaNama, 20/05/2025). After the header you'll also see a type suffix, which came in with the 2025 amendment, so a promotion shows -P, a service message -S, a transactional one -T and a government message -G.

DLT template rules: categories, variables, one header each

A content template is your message written out in full before you ever send it, a fixed part plus variable parts for things like a date or a reference number. Every time you send, the operator holds the message up against that registered template, and if it doesn't match, it doesn't go.

Those examples are our own reading of TRAI's definitions rather than TRAI's words, and the operator's registrar checks the category you pick when it approves each template. Login OTPs are where the rules just changed. The 2025 transactional definition named "apps login" OTPs, but the Third Amendment deletes those words and lists "OTPs for authentication, such as app login, password reset, two-factor authentication" under service messages. Neither category is checked against DND. If your buyer-portal OTP is registered as transactional, ask your telemarketer whether the operator wants it moved now that the amendment is in force.

• Three variables, normally. More need special circumstances, written justification, each variable pre-tagged for its purpose and at least 30% of the template fixed (TRAI's direction of 12/05/2023, as NovoJuris Legal summarises it).
• Thirty characters per variable. Longer values need justified contiguous variables, so keep a project address in the fixed text.
• Tag every variable. Under TRAI's direction of November 2025, each variable carries a tag such as #number#, #url# or #cbn# (call-back number), and the operator checks the value against it. Once the 60-day grace period ended, a value that fails its tag, such as "2,500.00" in a #number# field, is blocked (MediaNama, 19/11/2025).
• Fixed text is fixed. After approval only the variables change. New wording needs a new template.
• Carry your brand. The Vilpower FAQ says templates should contain the business or brand name and could be rejected without it; OTP templates without one were treated as invalid after 31/10/2020. Both FAQs allow Hindi and other Unicode templates.
• Get the category right. Since TRAI's direction of 20/08/2024, a template registered in the wrong category is blacklisted, and five blacklisted templates suspend the sender's services for a month or until its templates are re-verified (Khaitan & Co's summary). From 90 days after the Third Amendment's publication, the regulations count five within 90 days and apply whichever period is later.

Consent, DND and promotional hours

Customers set preferences through 1909, by call, SMS or USSD: block all promotions ("BLOCK PROMO") or block a category. Under the Third Amendment the old "fully block" choice moves into BLOCK PROMO, and no preference blocks transactional or service messages. Real estate is category 2, so "BLOCK 2" sent to 1909, or *1909*2#, stops real estate promotions to that number.

• Who gets promotions. Only numbers that have not blocked the category, or whose explicit consent sits on the operator's consent register. The Vilpower FAQ says consent given to you overrides a blocked category.
• When. The default band for promotions is 10:00 to 21:00, so they go out in those hours unless the customer switches more bands on. The Third Amendment says transactional and service messages are not blocked in any time band.
• Opt-out. Every promotional message must carry an opt-out option.
• Explicit consent. You register a consent template with its purpose and how to revoke it, and the customer confirms digitally. The operator sends the consent request from a 127xxx short code, or another code or header TRAI specifies. If a customer opts out, you wait 90 days before asking them again, however keen the sales team is.
• Enquiries. Under the Third Amendment, a written or digital enquiry supports messages for seven days and must be "maintained in a verifiable form by the Sender"; an application supports three months. TRAI's explanatory note says senders often cite an "oral inquiry" when customers complain. Keep the portal lead or form submission, with its date and source, in your lead record; our real estate lead management guide covers that intake.
• Old consent lists. Under the Third Amendment, earlier consents count only if obtained by verifiable means and registered on the consent register.

TRAI's consent is only permission for commercial calls and SMS. The DPDP Act's consent rules are a separate law, and the Third Amendment says nothing in TRAI's rules exempts a sender from that Act; see our DPDP Act compliance checklist for real estate.

A project promotion is also an advertisement under the RERA Act, 2016, which covers publicity "in any form", so section 11(2)'s authority website address and project registration number belong in the fixed text.

What changed in 2024 for whitelisting and chain binding

A lot changed in 2024, so if your SMS was set up back in 2020 or 2021, go through this table.

This table's facts come from TRAI press releases 53/2024, 60/2024, 67/2024, 80/2024 and 92/2024, plus Khaitan & Co's summary of the 20/08/2024 direction. The last release, as Storyboard18 reported it, counts about 1.13 lakh active principal entities, naming real estate among their sectors. TRAI's releases 11/2025 and 119/2026 summarise the 2025 and 2026 changes.

Why OTPs and reminders don't arrive

Start with one failed message. Ask your SMS provider for its delivery status and failure reason, then find the row.

Before you promise buyers an OTP

• An entity ID for the company whose name the message carries.
• A letter header for OTPs and service messages, a number header for promotions.
• An OTP template with your brand and one tagged variable, in the category your portal accepts for authentication codes.
• Reminders without offers, a declared chain and whitelisted links.
• A second route, such as email, for when SMS fails.

We follow this ourselves. Saudaflow sends no sign-in codes by SMS while the sender and template registration our two-factor help page mentions is still pending; staff sign in with an email and a password. That's also why Buyer Connect points buyers to a one-time code by email for now, while SMS delivery stays blocked.

This guide was checked against TRAI's Telecom Commercial Communications Customer Preference Regulations, 2018 (consolidated text of 21/05/2026), its 2025 and 2026 amendments with their explanatory memoranda, TRAI press releases of 2024 to 2026, the Vilpower and BSNL DLT FAQs, and sections 2(b) and 11(2) of the RERA Act, 2016, on 16/10/2026. We went through it again on 22/10/2026 with the Third Amendment's Gazette text (the copy hosted by TeamLease RegTech), PIB's release of 12/02/2025, the Vilpower and BSNL FAQs and the summaries by Khaitan & Co, NovoJuris Legal, MediaNama and Storyboard18. It's general information and it's not legal advice, so for your own case, talk to your advocate.