What Is Calling Line Identity (CLI or CLID)?

What Is CLI? – CLI Meaning

CLI stands for Calling Line Identity. It is a telephone service that displays the caller’s phone number to the person receiving the call. You may recognise it as Caller ID, the name commonly used by BT and other telephone providers.

When someone calls your mobile phone, you will usually see their number on your screen before you answer. This is a common example of CLI in action. However, the technology is also important in business communications, particularly in contact centres.

How Does CLI Work?

When someone makes a phone call, the telephone network can transmit information about the calling number to the receiving phone system. This allows the recipient to see the caller’s number before answering the call.

The information can help businesses identify incoming callers and manage calls more efficiently. However, the number displayed may be withheld, unavailable or, in some cases, different from the number the caller is using. Organisations should not assume that CLI always provides a verified identity.

Why Is CLI Important in Contact Centres?

Contact centres can use CLI alongside Computer Telephony Integration (CTI) software to improve how agents handle incoming calls.

For example, when a customer calls, the CTI system can use the incoming telephone number to search the organisation’s customer database. If it finds a matching record, it can display relevant information on the agent’s screen before or during the conversation.

This process is often called screen popping. It can help agents access customer details more quickly, reduce the need to ask customers to repeat information and support a smoother customer experience.

CLI can also help contact centres analyse incoming call patterns, identify repeat callers and route calls according to their telephone numbers, where the system supports this functionality.

What Is the Difference Between CLI and ANI?

In the UK, CLI stands for Calling Line Identity. In the USA, a similar concept is known as Automatic Number Identification (ANI).

Although the terms are related, they are not always interchangeable. ANI is associated with identifying the originating telephone number in telephone networks, particularly in North American telephony. CLI is the more familiar term in the UK.

Both can provide useful calling-number information to telephone systems, helping businesses manage incoming calls and support their contact centre operations.

Reviewed by: Megan Jones