Telecom Glossary

26 essential Indian telecom terms explained in plain English.

A

ARPU: Average Revenue Per User. A telecom KPI measuring monthly revenue divided by subscriber count.

C

Carrier Aggregation(CA): Combining two or more LTE/5G bands to increase data throughput on a single device.
Circle: India is divided into 22 telecom service areas (circles) for licensing. Plan pricing and benefits can vary by circle.

D

Data Rollover: Unused data from one billing cycle carrying over to the next. Common on postpaid plans, rare on prepaid.
DND(Do Not Disturb): TRAI service that blocks promotional SMS and calls. Activate by SMS 'START 0' to 1909.

E

eSIM: Embedded SIM stored in device hardware. Activated via QR code without a physical card. Supported on all four Indian operators.

F

FUP(Fair Usage Policy): Speed cap applied after a daily or cycle data quota is exhausted. Typically throttles to 64–128 Kbps.

I

IUC(Interconnect Usage Charge): Fee one operator pays another to terminate a voice call on its network. Mostly zero in India since 2021.

J

Jio True 5G: Jio's 5G Standalone (SA) network, launched 2022. Unlimited 5G data is bundled on most prepaid plans above Rs 239.

L

LTE(Long Term Evolution): 4G mobile broadband standard. The baseline technology across Airtel, Jio, and Vi.

M

MNP(Mobile Number Portability): Process of switching operator while keeping the same number. Send 'PORT <number>' to 1900.
MNP Lock Period: After porting, the number cannot be ported again for 90 days.

N

NSA(Non-Standalone 5G): 5G that uses an existing 4G core for signalling. Airtel India 5G is NSA-based.

O

OTT(Over The Top): Streaming services like Netflix, Hotstar, JioCinema bundled with telecom plans.

P

Postpaid: Use first, pay at month-end against a bill. Usually includes data rollover and family add-ons.
Prepaid: Pay in advance for a fixed validity pack. Service stops when the pack expires.

R

Roaming: Using your home SIM on another operator's network. National roaming is free in India since 2015.

S

SA(Standalone 5G): 5G that uses a dedicated 5G core. Enables network slicing and lower latency. Jio uses SA.
SIM Swap: Replacing a damaged SIM or upgrading to a 5G/eSIM. Done at operator stores with ID proof.

T

Tariff: The official price list of a telecom plan filed with TRAI.
TRAI(Telecom Regulatory Authority of India): Government body that regulates telecom tariffs, quality of service, and consumer protection.

U

USSD(Unstructured Supplementary Service Data): Short codes like *121# used to check balance, validity, and recharge without internet.

V

Validity: Number of days a prepaid plan remains active. Calls, SMS, and data stop at expiry unless renewed.
Vo5G: Voice over 5G New Radio. Limited rollout in India as of 2026; most 5G calls still fall back to VoLTE.
VoLTE(Voice over LTE): HD voice calling carried over the 4G data network. All Indian operators have shut down legacy 2G/3G voice for VoLTE.

W

Wi-Fi Calling: Voice calls placed over a Wi-Fi network when cellular signal is weak. Supported by all four operators.