A/338, “Companion Device”Approved: 3 April 2024

This document specifies the communication protocol between an ATSC 3.0 primary device and an ATSC 3.0 companion device. In this context, the primary device is the primary receiver and is used to present the primary content. The companion device communicates with the primary device to present related, supplementary content, or even the same content as that being presented on the primary device. Examples of primary devices include television sets, set-top/converter boxes, and mobile devices that are capable of receiving ATSC 3.0 services. Examples of companion devices are laptops, tablets, and smartphones.

Download current version: A/338:2024-04, “Companion Device”, 3 April 2024, and accompanying schema. This version of the Standard is normatively referenced in A/300:2024-04.

Previous Versions

There are multiple versions of this document. Please be sure to download the desired version. For amendments, the text includes a list of changes, the rationale for the changes, and compatibility considerations.

Download A/338:2017, “Companion Device”, approved 17 April 2017. This version of the Standard is normatively referenced in A/300:2019.

Download A/338:2019 “Companion Device”, approved 2 October 2019. This version of the Standard is normatively referenced in A/300:2020.

Download A/338:2019 Amendment No. 1, “CD Event Stream API”, approved 21 January 2020.

Download A/338:2021, “Companion Device”, approved 19 February 2021. This version of the Standard is normatively referenced in A/300:2021.

Download A/338:2022-01, “Companion Device”, approved 17 January 2022, and accompanying schema.

Download A/338:2022-03, “Companion Device”, and accompanying schema, 31 March 2022. This version of the Standard is normatively referenced in A/300:2022-04.

Download A/338:2023-03, “Companion Device”, and accompanying schema, 28 March 2023. This version of the Standard is normatively referenced in A/300:2023-03.