The Firefly 300MCD21K Linear Multi-Code Compatible Remote is a compact handheld transmitter designed to operate gate operators, garage door openers, and access control systems that use the Linear/Multi-Code fixed-code format at 300 MHz. Built for straightforward replacement and expansion, it provides reliable, everyday control for residential and commercial applications where Multi-Code 300 MHz receivers are installed. It is ideal as a replacement remote for existing Multi-Code systems or as an additional transmitter for shared access points.
This remote uses the classic Multi-Code fixed-code protocol with an internal DIP-switch bank, allowing quick programming by matching the switch pattern in the receiver or an existing working transmitter—no learn-button or rolling-code pairing required. Operating on the 300 MHz band, it is compatible only with Multi-Code format receivers and operators and will not work with rolling-code formats such as LiftMaster Security+ 2.0 or Genie Intellicode. For best results, program the DIP switches to precisely match the host system and verify the system operates on Multi-Code at 300 MHz before purchase or installation.
How to Program a Firefly 300MCD21K Multi-Code Remote
1. Remove the screw from the back of the remote. Push the sides of the remote together long ways. This will create a gap in the remote to put your fingernail in to push the remote apart.
2. Locate the 10 switch code on the receiver or a working remote. Your garage or gate will have an external receiver that will have the 10 switch code in it. If you have a working remote it is usually easier to use the switches from the remote.
3. Move the switches in the new remote so they are in the same order as the receiver or working remote.
4. Press the remote. The garage or gate should operate. If the remote does not work then reverse all the switches.
To download the manufacturers instructions click here.