mikem
23 Aug 2009, 06:53
I would an ad insertion module. This would be mostly for small commercial TV stations. The way ad insertion works in broadcasting is DTMF "start" tones (usually 4 of them such as 123*) are sent approximately 7 seconds before the break on an unbroadcasted audio channel. You might have heard these while watching TV and wondered what they were. At the end of the 7 seconds the commercial is switched to the program output. It might be one or more commercials but regardless, the output is switched back to the normal program at a preset length of time (usually 30 to 120 seconds) or when another set of DTF "end" tones are sent (in this case 123#) or both using timer as a safety just incase the DTMF tones weren't sent. Then the output is changed back to the originalvideo input.