Linear megacode mdrm User Manual

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Scale: 1-1

Side 1 

of 2

Installation Instructions

(800) 421-1587 

•

 www.linearcorp.com

The MegaCode series of digital receivers are wireless radio
controls designed for use with automatic garage door and gate
openers. The MegaCode radio format provides unparalleled
security. The transmitter and receiver can be programmed to more
than a million different codes.
MegaCode receivers and transmitters do not contain a typical
“coding switch”. Each transmitter is pre-set at the factory to a
unique code. The receiver is programmed by sending a signal to
it from the transmitter(s) that are going to be used with it. This
stores the transmitters code into the receiver’s memory. The
receiver will retain its memory even without power. The receiver
will activate only from these “memorized” transmitters. Each
M egaCode  receiver can  remember a maximum of 10
transmitters.
Receivers are normally powered with 24 volts AC/DC from the garage
door or gate operator. Two-channel receivers provide wire
connections to activate the operator’s light or control other devices.

MDR - Single-channel external receiver with relay output.
MDRM - Single-channel internal receiver (fits operators with
recessed receivers) with solid state output.
MDRNR - Single-channel external receiver with solid state output.
MDR2 - Two-channel external receiver with relay outputs.
MDRM2 - Two-channel internal receiver (fits operators with
recessed receivers) with solid state output on channel one and
relay output on channel two.

Installation. Hold receiver up to back of operator. Connect
Terminals 1, 2 & 3 on the receiver to Terminals 1, 2 & 3 on the
operator.

Installation. Loosen operator terminal screws. Install receiver
into operator “pocket”. Connect Terminals 1, 2 & 3 on the receiver
to Terminals 1, 2 & 3 on the operator.

The Model TF524 step-down transformer must be used to power
the receiver when connecting to a two-terminal operator or one
that supplies other than 24V. Install the screws supplied into the
brass terminals on the receiver. Connect the transformer wires to
Terminals 1 & 3 (polarity not important). Connect receiver
Terminals 1 & 2 to the two operator terminals (polarity not
important).

Connect the receiver to the operator as described in the previous
step. The channel-two pigtail wires can be connected to the
operator’s light toggle terminals or to an external device.

Optional Receiver Mounting Bracket. If the receiver

isn’t going to be mounted directly to the operator terminals, an
optional mounting bracket is supplied. It can be installed three
ways onto the MDR or MDR2 case. Screw the bracket to a wall
or stud and snap the receiver onto it.

Location. Locate the program button and LED on the side of the
receiver case.

1

2

3

1

2

3

CONNECT
RECEIVER
DIRECTLY
TO OPERATOR

MATCH UP
TERMINAL
NUMBERS

COMMON

GROUND

RELAY

24-VOLTS

RADIO

POWER

RECEIVER FITS INTO
BACK OF OPERATOR

BRASS
TERMINALS
FIT TO 
TERMINALS 
1, 2 AND 3

ANTENNA

COMMON

GROUND

RELAY

24-VOLTS

RADIO

POWER

1

2

3

INSTALL 3 SCREWS

WIRE TRANSFORMER TO TERMINALS 1 & 3

USE MODEL
#TF524 24VAC, .5VA
TRANSFORMER

WIRE TERMINALS 1 & 2 TO OPERATOR 
PUSHBUTON TERMINALS

CONNECT ORANGE TO LIGHT TERMINAL

GROUND (#1)

BROWN

ORANGE

RED

RELAY

COMMON

RELAY

NORMALLY

OPEN

RELAY

NORMALLY

CLOSED

3-TERMINAL

OPERATOR

RECESSED RECEIVER

OPERATOR

CONNECT BROWN TO COMMON GROUND

LIGHT

TERMINAL

(#0)

BRACKET CAN
MOUNT IN THREE
PLACES

LOCATION 1

LOCATION 2

LOCATION 3

CORNER HOLE IS
SHARED FOR
LOCATIONS 2 & 3

MDR2

MDR
MDRNR

MDRM

MDRM2

TWO

CHANNEL

SINGLE

CHANNEL

CHANNEL TWO 
PROGRAMMING
BUTTON (ONLY
ON MDR2)

CHANNEL ONE 
PROGRAMMING
BUTTON

PROGRAMMING
LED