2
131 EISENHOWER LANE NORTH
LOMBARD, ILLINOIS 60148
630-268-0010 / 1-800-251-2408
MONOPLEX SPEAKER SWITCH
INTELLITEC
PRODUCT DESCRIPTION
The MONOPLEX Speaker Switch is intended to be used in conversion vehicles to switch the rear speak-
ers from a radio to the TV. This allows the TV sound to be brought out through the rear speakers. The
module is designed so it can work with an audio amplifier that has a control input that turns the amplifier
on or off.
When the ignition is turned on, the rear speakers will be muted. The power to the amplifier will be turned
off. At the first press of the switch, the speakers will be connected to the radio inputs and the amplifier is
turned on.
The next press of the switch will connect the speakers in series and turn on the amplifier, bringing the TV
sound out of the rear speakers. The third press will mute sound. Then the process is repeated.
HOW IT WORKS
The MONOPLEX Speaker Switch provides a means of switching the two rear speakers to allow switching
between the four radio inputs and two TV inputs. The actual switching is done with relays. These relays
are controlled by the control electronics to provide the functions of the unit. When the unit is not pow-
ered, the speakers are connected in series, but are not connected to any signal source. There is no
amplifier power. At the first press of a remote switch, (a short to ground on the MPX bus) relays K1, K2
and K4 are pulled in, connecting the radio inputs to the speakers and providing power to the amplifier. At
the next press of the switch, relays K1 and K2 drop out and relay K3 pulls in, connecting the speakers in
series to the TV set. At the next press of the switch, relays K1, K2, K3, and K4 drop out , disconnecting
the speakers and removing power to the amplifier, to repeat the cycle.
Power for the control electronics is provided from the back lighting circuit. When this power is applied,
the system will come up in the mute mode.
