The squelch (or silencer) is a control found on all CB radio transceivers. This function is used to reduce background noise when there is no communication.

It is an adjustment which must be made precisely and repeated frequently in order to avoid reducing the reception capacities of the radio.

This is because the level of radio-electric background noise is not constant and varies according to the time of day and the geographical location.

In April 1996, Albert Bertrana, Technical Director of the Groupe PRESIDENT, presents to the specialized press an automatic squelch adjustment system called "Automatic Squelch Control" (ASC).

ASC, innovation GROUPE PRESIDENT ELECTRONICS, continuously evaluates the received signal and existing noise. The signal/noise ratio determines whether a signal is heard or not. Applying surface mount package and microelectronic technologies, ASC uses more than 40 semiconductors, between transistors and diodes.

CB radios, which have always been a security element in vehicles, are now even more so since drivers will no longer have to make manual adjustments, or check the noise level, since ASC does this for them.