Short answer: In India, promotional voice calls must come from 140-series numbers, and service or transactional calls from banks, NBFCs, insurers, brokers and government bodies must come from 1600-series numbers. In July 2026, TRAI clarified that 1600-series calls cannot be tagged, blocked or filtered by any app, and that 140-series calls can only be blocked through the customer’s own DND preferences — not by third-party spam apps.
If you run voice broadcasts, reminder calls or IVR surveys, this changes how your calls are identified, delivered and trusted. Here’s what you need to know.
What the two series are for
| 140xx series | 1600xx series | |
|---|---|---|
| Purpose | Promotional calls | Service & transactional calls |
| Who uses it | Any business, any sector | Entities regulated by RBI, SEBI, IRDAI, PFRDA — and government-to-citizen communication |
| Can customers block it? | Yes, via the DND registry (by sector or all sectors) | No |
| Can spam apps tag or filter it? | No (only DND-based blocking applies) | No |
| Registration | Register with your telecom operator under TCCCPR | Allocated to eligible regulated entities |
The idea is simple: a customer who sees 1600 on their screen knows it’s their bank or a government office, and a customer who sees 140 knows it’s marketing they have not opted out of.
Why TRAI issued a clarification
Media reports in mid-2026 suggested some confusion about whether these calls could be blocked or labelled as spam. TRAI’s press note set the record straight: tagging 1600 calls is not allowed under the Telecom Commercial Communications Customer Preference Regulations (TCCCPR), and tagging 140 calls could mislead customers who have chosen to receive promotions from certain sectors.
The numbers behind it
TRAI’s own figures for Q1 of FY 2026-27 show how big this system already is:
- 13.16 billion promotional calls originated from 140-series numbers
- 1.48 billion of those were blocked after checking customers’ DND preferences
- 1.15 billion calls originated from 1600-series numbers
- 248 billion commercial SMS went through registered senders, with 7.3 billion promotional SMS blocked by DND
In other words: roughly 1 in 9 promotional calls from 140 numbers was blocked because the recipient had opted out of that sector. Plan your list sizes and budgets with that in mind.
What this means for your campaigns
1. Classify every campaign before you dial. Offers, launches and lead generation are promotional (140). OTPs, payment confirmations, account alerts and EMI reminders from regulated BFSI entities are service/transactional (1600). If you’re not a regulated entity, you don’t get 1600 — don’t try to dress promotions up as service calls.
2. Budget for DND loss. Promotional calls to DND-registered numbers will be dropped. Clean your list against DND preferences before a campaign so your reports and costs reflect people you can actually reach.
3. Register your templates on DLT. Promotional voice campaigns need entity and template registration on your operator’s DLT platform, the same way SMS does. Register the exact opening lines you’ll use.
4. Say who you are in the first five seconds. A 140 prefix already tells the listener it’s marketing. What earns you the next 25 seconds is naming your brand and the reason for the call immediately.
5. Check where surveys fall. Survey and research calls don’t always sit neatly in one category. Confirm the classification with your operator before you run a large IVR survey — the answer decides which number series and which DND rules apply.
6. Stop calling from ordinary 10-digit mobile numbers. Commercial calls from regular mobile numbers are exactly what TRAI’s AI-based spam detection is built to flag. Moving to the designated series is both the compliant and the better-delivered option.
Quick checklist
- Every campaign mapped to promotional or service/transactional
- Principal Entity and templates registered on DLT
- 140-series number(s) provisioned through a registered provider
- List scrubbed against DND before each campaign
- Opening line names the brand and purpose
- Reports separate “DND-blocked” from “unanswered”
Frequently asked questions
What is a 140 series number? A TRAI-designated number range that businesses in any sector must use for promotional voice calls in India. Customers can block these calls by sector through the DND registry.
What is a 1600 series number? A number range reserved for service and transactional calls from entities regulated by RBI, SEBI, IRDAI and PFRDA, and for government-to-citizen communication. These calls cannot be blocked, tagged or filtered.
Can Truecaller or other apps mark 140 calls as spam? According to TRAI’s July 2026 clarification, 140-series calls cannot be tagged or filtered except through the customer’s registered DND preferences.
Can a non-financial company get a 1600 number? No. The 1600 series is limited to BFSI entities regulated by the four financial regulators and to government communication.
Do I still need DLT registration for voice calls? Yes. Promotional voice campaigns require entity and template registration on your telecom operator’s DLT platform.
Regulations change. This article reflects TRAI’s July 2026 press note and Q1 FY 2026-27 data; check trai.gov.in or your telecom operator for the latest rules before launching a campaign.
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Sources: TRAI Press Release No. 111 of 2026 (Q1 FY 2026-27 statistics); TRAI press note on 1600 and 140 series, July 2026.