scope:

This technical report provides a framework for signaling verified Caller ID information from the network to a User Equipment (UE) and displaying the information on the UE in a uniform manner, independent of technology. The main goal is to provide display guidelines that help empower consumers in managing their calls, as per the Robocalling Strike Force recommendations¹.

This report should be treated as a living document as the guidelines are expected to evolve. The deployment of verification methods, such as Secure Telephone Identity Revisited/Signature-based Handling of Asserted information using toKENs (STIR/SHAKEN), and application of call analytics are expected to occur in stages over an extended period of time. Hence, the operations experience gained over time is expected to provide feedback and input to future issues of this report.

Results of usability studies are expected to contribute to the evolution of the recommendations in this report, as they become available.

More research is needed to identify the types of displays that empower end users with messages that are easy to interpret. At this time, such research is outside the scope of this report.

Purpose

The guidelines presented in this document are best practices based on a review of industry standards and studies on the effectiveness of warning signs and human factors related to the reading and comprehension of variable messages (text and symbolic). These guidelines help meet the goals of regulators and consumer protection agencies for empowering consumers with simple and effective call information.

This report recommends that these guidelines be taken into consideration by all stakeholders (service providers, equipment manufacturers, and analytics providers) in the deployment of verified Caller ID displays and the composition of its related messages.

Variations may exist, subject to local policy.