DND (Do Not Disturb) is a service provided by telecom operators to protect subscribers from unsolicited calls and messages. The service allows subscribers to choose what messages they want to receive from various networks when they activate the DND on their phone lines at no extra cost. The DND service has two specific features: Full DND and Partial DND. Full DND allows subscribers to opt-out entirely from receiving any unsolicited messages via SMS, while Partial DND allows subscribers to filter out service categories for promotional messages they wish to receive.

The DND service is available in different countries, and the process of activating it may vary depending on the telecom operator. For example, in Nigeria, all service or telecom operators have been mandated by the NCC (Nigerian Communication Commission) to implement a Do-Not-Disturb policy and also set aside a Common Short Code (2442), which would enable subscribers to take necessary actions regarding unwanted text messages or bulk SMS. In India, DND is an initiative by TRAI (Telecom Regulatory Authority of India) to save telecom consumers from unsolicited calls/SMS.

It is important to note that DND is different from the "Do Not Disturb" feature found on smartphones. The "Do Not Disturb" feature on smartphones allows users to mute notifications, calls, alerts, and text messages.