Talkback and Commentators Unit for the Calrec "J" Series sound desk installed at Millbank by the BBC for broadcasting from the House of Commons.

Proposals for live coverage from the House of Commons were first discussed by Parliament in 1964. Following test transmissions in 1975 this equipment was part of the permanent installation made by the BBC in 1978 to broadcast live radio coverage. Broadcasts were made on Radio 4 and clips included in review programmes such as Today in Parliament. Television coverage was introduced in 1989 and is now broadcast as BBC Parliament.

The Calrec "J" series sound desk was designed for the BBC. Large numbers were produced and it was used extensively for outside broadcast & on location recordings.

This module was a bespoke unit added to the main “J” series console components. The commentator unit was used for live feeds and remote ‘down the line’ interviews. As interviews were organised at very short notice the BBC installed limiters to the signal lever as there was no time to set a proper level.

The "J" Series came in modules comprising eight channels, eight stereo groups and auxiliaries, and an output unit with monitoring and metering which were hooked together with multicores. Up to 72 channels could be cascaded to make a very large sound desk that still was manageable for transport. Each unit had built-in carrying handles and could be lifted by one person. Modules could be hot-swapped to extend the required number of inputs whilst broadcasting without causing thumps on the output.