User friendly 12-Channel professional rebroadcast grade audio-video emergency alert system. Enables users, via a local or remote contact closure to simultaneously override up to 12 AV channels (monaural or BTSC stereo) with one override AV source. Alternately, the unit can be daisy-chained to override 23 channels with an audio or video-only override source. Interrupts the primary signals at baseband level instead of breaking into the I.F. loop, eliminating the signal distortion and loss associated with traditional I.F. switching. Compatible with all I.F. loop and non I.F. loop modulators. Units may be cascaded to add channels. All connections are via industry standard "F" type coaxial jumpers. 5-year limited warranty.