How it works on Indian calls
The 1600 series comes from TRAI's rules under the TCCCPR. TRAI's February 2025 amendment (press release No. 11 of 2025) put service and transactional calls on the 1600 series and promotional calls on the 140 series. Ordinary 10-digit mobile and landline numbers can't be used for commercial calls.
Regulated finance moved first. TRAI's direction of 19 November 2025 requires banks, financial services firms and insurers to use 1600xx numbers, and only those, for their service and transactional calls. The dates reported for the switch, from that direction and IRDAI's circular of 6 January 2026, are:
| Switch date | Who |
|---|---|
| 1 January 2026 | Banks |
| 1 February 2026 | Large NBFCs, small finance banks and payments banks |
| 15 February 2026 | Insurers |
| 1 March 2026 | Remaining NBFCs, regional rural banks and co-operative banks |
A July 2026 direction phases in mandatory 1600-series use, sector by sector. Ask your operator which date applies to you before you plan around it.
The Third Amendment of 18 September 2026 (PIB release ID 2311989) adds protection: 1600 numbers must not be shown as spam, and caller-ID apps may not block or spam-tag them wholesale.
Why it matters
A 1600 number tells the person, before they pick up, that the call is about a service they already use and not a sales pitch. That's also why the script has to stay on purpose: a service call shouldn't turn into an offer.
How Kallix handles it
Kallix helps you get 1600-series numbers through Vobiz, issued in your business's name, for sectors whose service and transactional calls must use them, and declares automated (A2P) calling for those numbers. Run EMI reminders, renewal notices and other service calls as their own campaigns, apart from promotions on the 140 series.