[Orry Verducci]

+1 channels vary depending on the broadcaster and playout facility, and of course cost.

Some broadcasters will choose to operate them as their own independent automation playlists, just with everything scheduled an hour later, maybe with different ads/promotions/etc. More commonly however they are recording to a video server, replayed an hour behind.

Some broadcasters record this from the final output of the main channel and stick a +1 DOG on top. Others have more sophisticated playout setups which record downstream of graphics being inserted and automatically replay the graphic events an hour later to insert new DOG's with +1 branding, which allows the +1 DOG to be switched on/off at the same time the main channel did.

With respect to terminology, playout and TX are the same thing. Playout areas, in the UK at least, are commonly called "Transmission" or "Presentation". I think bbctvtechop may have been thinking of distribution, which is the path between playout and viewers at home