New Mission Critical Broadband Callout – Key documents published

December 1 2025 – The extensive work of a task force within TCCA’s Critical Communications Broadband Group (CCBG) has led to the creation of new mission critical broadband callout specifications compatible with 3GPP MCX standards, using MCData SDS and MCPTT. The two new critical documents are the Mission Critical Broadband Callout Service Overview with requirements and use cases, and the Mission Critical Broadband Callout Service Definition with the detailed specifications.

Callout is a two-way paging service that enables a control room dispatcher to select the first responders that should respond to an incident and send them callout alerts with a description of the incident situation. Users can respond back to the dispatcher informing if they are available to attend the incident or not.

The TETRA callout specifications were developed by TCCA in 2009 and allow callout to work between dispatch systems and radio terminals from different manufacturers, as long as the specifications are followed. Callout is a vital service in TETRA networks but has, to date, not been available for 3GPP 4G and 5G broadband mission critical networks.

Now available at two levels for critical broadband, Simple Callout uses text messages only, to alert users and collect user responses, while Full Callout includes a two-way information phase in which the dispatcher and users can talk in the MCPTT callout group and exchange MCData text information about the incident during the callout.

“With mission critical broadband callout specifications, TCCA complements the 3GPP standards to enable further mission critical functionality over 3GPP MCX networks in a common way” said Tero Pesonen, CCBG chair. “This is a significant step we are taking in serving the critical communications community”.

With the new TCCA broadband callout specifications now in place, first responders can be called out to respond to incidents no matter who makes and delivers MCX clients and dispatch systems, as long as the products follow the specifications. These support callout of users belonging to different user groups or agencies, and across country boundaries.

Access the documents here.