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206-4281
3
TV
ON/OFF
CHAN
DOWN
CHAN
UP
(MALE
PLUG)
VOLUME CONTROL
SPKR
5
1
4
6
2
Typical Schematic for
Analog Pillow Speaker
Reference: Pillow Speaker Setup (Cont.)
22/28LX570M
All lines are isolated from the AC power line (optoisolators isolate the
control lines, and a transformer isolates the audio). Earth ground is
provided on pin 4 (Common) in the default configuration (e.g., for
Zenith/Philips pillow speakers). For negative voltage configuration (e.g.,
for RCA pillow speakers), +5 volts is provided on pin 4 (Common), with
pin 3 (Channel Up/Data In) referenced to ground.
32/43LX570M
All lines are isolated from the AC power line and earth ground (a
transformer isolates the DC supply, optocouplers isolate the control
lines, and a transformer isolates the audio). For positive voltage
configurations (e.g., for Zenith/Philips pillow speakers), +12 volts/+5
volts is provided on pin 3 (Channel Up/Data In) in reference to pin 4
(Common). For negative voltage configurations (e.g., for RCA pillow
speakers), +5 volts is provided on pin 4 in reference to pin 3.
Controlling the TV with Mechanical Switches
A typical analog pillow speaker with mechanical switches will momentarily
connect pin 1, 3, or 6 to pin 4 (Common) to control Power ON/OFF,
Channel Up, or Channel Down (see schematic at right). These pins are
at +13 volts DC (when measured from pin 4) with the switches open.
Typical current draw is 8 mA when a switch is closed. (This operation is
identical to previous models using the 5-wire interface, except that only
+7 volts DC was supplied and current draw was only 2.5 mA.)
