The touch tone pad is connected to a 75.3 MHz Catel FM audio modulator we call the aquot;Order Wire. ... The FM video, the audio and order wire signals are amplified by a Tomco A1 10A amplifier to drive the AML transmitter at the correct level. ... Audio from the 75.7 MHz FM audiAc demod is fed to the Channel 12 modulator. ... Figure 7 is the Hub I block diagram and is much like the Hub II configuration. Noteanbsp;...