📞 AI voice calling

TRAI's 140, 1600 and 1601 number series: which one your AI calls need

Updated 2026-10-22 · 5 min read · By the Convo360 team

In short

Under TRAI's rules, promotional calls in India must come from 140-series numbers by a registered sender, and DND preferences apply. Service and transactional calls from banks, insurers, investment firms and government use the 1600 series. From 10 August 2026, utilities, courier and logistics companies move their service calls to the new 1601 series. An AI caller follows exactly the same rules as a human one.

Key takeaways

Normal 10-digit mobile numbers are not meant for telemarketing under the February 2025 TCCCPR amendment.
Promotional calls come from 140-series numbers, and a customer's DND sector blocks still apply to them.
The 1600 series is for service and transactional calls from RBI, SEBI, IRDAI and PFRDA regulated entities and government.
TRAI's 10 August 2026 direction gives utilities, courier and logistics firms the 1601 series, with 90 days for telecom operators to onboard them.
Decide whether each AI campaign is promotional or service before you choose the number it calls from.

The three number series at a glance

India's telecom regulator now tells customers what kind of call they are getting from the number itself. This page summarises TRAI's own press releases as read on 21 October 2026. It is a plain explanation, not legal advice, so confirm your position with your telephony provider and the official text.

Series	Who uses it	Type of call	DND applies?
140xx	Registered senders in any sector	Promotional	Yes, by sector preference
1600xx	Entities regulated by RBI, SEBI, IRDAI and PFRDA, plus government	Service and transactional to existing customers, government to citizen	No tagging, blocking or filtering allowed
1601xx	Phase I: utilities, courier and logistics	Service and transactional only	Promotional use is not allowed

The point of all three is trust. When a customer sees 1600 or 1601, the call is meant to be a genuine service call from a verified business. When they see 140, they know it is a sales call, and they can block it by sector.

What the February 2025 TCCCPR amendment changed

On 12 February 2025 TRAI amended the Telecom Commercial Communications Customer Preference Regulations, 2018. Several changes matter directly to anyone dialling customers with an AI agent:

No 10-digit numbers for telemarketing. Commercial calls must come from designated headers or number series: 140 for promotional, 1600 for transactional and service.
Consent for an ongoing transaction lasts 7 days. You cannot keep calling for weeks on the strength of one enquiry.
Implied consent for service calls ends with the contract. After that, you need explicit consent to keep calling.
After an opt-out, you cannot ask for consent again for 90 days.
Use of auto-diallers and robo calls must be disclosed and is regulated.
Operators watch calling patterns such as unusually high volumes, very short calls and a low ratio of incoming to outgoing calls, to flag likely spammers.

Penalties fall on the sender's telecom resources. A first violation of the threshold bars outgoing services for 15 days. Repeat violations mean disconnection of all resources, including PRI and SIP trunks, for a year, plus blacklisting. Customers can now complain within 7 days of a spam call, and action against an unregistered sender follows 5 complaints in 10 days.

The 1600 series: banks, insurers, investment firms and government

On 10 July 2026 TRAI issued a clarification after confusing media reports. The 1600xx series is mandated for service and transaction calls by entities regulated by RBI, SEBI, IRDAI and PFRDA to their existing customers, and for government to citizen calls.

TRAI also stated that under the TCCCPR, no tagging, blocking or filtering of calls from 1600 numbers is permitted. So an NBFC's EMI reminder from a 1600 number should reach the customer without a spam label.

The same release covers the 140 series. Any sector can use 140 numbers for promotional calls after registering with a telecom operator, and customers who block a sector on the DND registry will not receive 140 calls from that sector. Tagging of 140 calls is not allowed either, apart from blocking by DND preference. You can read it in TRAI press release 91/2026.

The new 1601 series for utilities, courier and logistics

On 10 August 2026 TRAI issued a direction extending the same idea beyond finance. The press release on the 1601 series sets out three provisions:

Phase I sectors. Utilities (electricity distribution, water, city gas, LPG distribution and similar) and logistics and courier services (courier, express logistics, parcel delivery, freight and logistics firms that deliver consignments).
90 days to onboard. Telecom operators were asked to migrate and onboard eligible Phase I entities within 90 days of the order.
Direct allocation and exclusive use. Numbers go to verified entities directly, not through intermediaries or aggregators, and the entity gives an undertaking to use them only for service and transactional calls. No promotional calls from 1601.

TRAI's stated reason is to stop fraudsters who use ordinary 10-digit numbers while pretending to be a legitimate business, and to keep important financial calls separate from other sectors' service calls.

What this means for your AI calling

An AI voice agent is simply another caller, so the number rules apply in full. Before you launch, sort every campaign into one of two buckets.

Promotional: offers, new launches, festive deals, cold outreach. Use a 140-series number through a registered sender, scrub against DND, and give a clear way to opt out.
Service or transactional: EMI reminders, delivery slot confirmation, bill due alerts, appointment confirmations. If you are in BFSI or government, that means 1600. If you are a utility or courier firm, plan your move to 1601.

If your sector is not yet covered, for example a clinic or a D2C brand, TRAI has not named it for 1601 so far. Ask your telephony provider which number type they will issue for your service calls, and keep promotions on 140.

Watch your calling pattern too. A campaign that blasts thousands of very short calls looks like spam to an operator's analytics, whether a person or an AI is speaking. Smaller batches, daytime hours and clean lists protect the number you depend on. Our guides to AI calling compliance and running an outbound AI campaign cover the rest of the checklist.

Setting this up on Convo360

Convo360 is bring your own telephony, so the number series comes from your own Exotel, Plivo, Twilio or SIP provider account. Convo360 adds no per-minute fee.

Get the right numbers from your provider: a 140 number for promotional campaigns, and a 1600 or 1601 number for service calls if your sector qualifies.
Connect each one under Phone Numbers, and assign a separate voice agent to each so a sales script never goes out on a service line.
Keep your DND list current. Campaigns skip anyone on it, and opt-out keywords such as STOP add a contact to DND automatically.
Capture consent through a form, keyword or checkbox, and use Audit Logs and call transcripts as your record.

Voice calls are on the Pro plan at ₹2,999 per month, excluding 18% GST. Setup details are in the compliance docs and the voice docs.

Example conversation

We are a courier company in Surat. Our AI agent calls customers to confirm delivery slots. Which number should it use?

Delivery slot calls are service calls, and courier firms are in Phase I of TRAI's 1601 series from 10 August 2026. Ask your telephony provider for a 1601 number, connect it in Convo360, and keep any promotional calls on a separate 140 number.

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Frequently asked questions

Can I make promotional AI calls from a normal mobile number?

No. TRAI's February 2025 amendment to the TCCCPR restricts the use of normal 10-digit numbers for telemarketing. Promotional calls must come from 140-series numbers through a sender registered with a telecom operator, and customers' DND preferences apply.

What is the 1601 number series?

It is a number series TRAI directed on 10 August 2026 for service and transactional calls from sectors other than BFSI and government. Phase I covers utilities and courier and logistics firms. Numbers go directly to verified entities and cannot be used for promotional calls.

Can a call from a 1600 number be marked as spam?

TRAI's clarification of 10 July 2026 says that under the TCCCPR, tagging, blocking or filtering of calls from 1600-series numbers is not permitted. The series is reserved for service and transactional calls from regulated financial entities and government communication.

Will customers on DND receive my 140-series AI calls?

Not if they have blocked your sector. TRAI says customers who block any or all sectors on the DND registry will not receive promotional calls from 140 numbers of entities in those sectors. Scrub your list before every campaign.

How long does a customer's consent for a transaction last?

Under the February 2025 amendment, consent given for completing an ongoing transaction is valid for 7 days. Implied consent for service calls lasts only for the duration of the contract, and after an opt-out you cannot ask for consent again for 90 days.

Does an AI voice agent follow different rules from a human caller?

No. TRAI's rules apply to the call, not to who or what is speaking. An AI agent must use the right number series, respect DND and consent, and honour opt-outs, exactly as a human calling team would.