Context:
The Department of Telecom (DoT) has instructed telecom operators to deactivate USSD-based call forwarding services, specifically the commonly used *401# service for unconditional call forwarding, with effect from April 15. The directive comes in response to concerns over the misuse of this facility for unauthorized activities. The DoT has urged telecom operators to transition to alternative methods for reactivating call forwarding services. This move aims to enhance security and prevent the misuse of USSD-based call forwarding, reflecting the government’s commitment to safeguarding telecommunications infrastructure and ensuring responsible use of telecom services.
Relevance:
GS II: Government Policies and Interventions
Unstructured Supplementary Service Data (USSD): An Overview
- Protocol: USSD stands for Unstructured Supplementary Service Data, a communications protocol utilized in Global System for Mobile Communications (GSM) networks.
- Nature: Unlike SMS (Short Message Service), USSD is an instant messaging service where messages are not stored on either the operator’s side or the subscriber’s device.
USSD Formats:
- USSD Pull:
- An outgoing request initiated by the user in the form of a MMI (Man-Machine Interface) command.
- USSD Push:
- A message sent from the operator to the user’s screen.
- Command Structure:
- USSD commands typically consist of special characters like * and #, followed by numeric codes.
- Commands start with * or # and usually end with #.
- Message Length:
- The maximum length for a USSD message is 182 characters. However, in practice, most requests are much shorter, often not exceeding 20 characters.
Applications:
- Balance Display:
- One of the common uses of USSD is to display balance deductions on mobile phones. For example, a message may pop up on the device screen after making a call or sending an outgoing SMS to show the remaining balance.
- IMEI Checking:
- USSD can also be used to check the International Mobile Equipment Identity (IMEI) numbers of mobile devices.
