Mega Code is Linear's 318 MHz radio format. Unlike the older Linear systems it has no dip switches — each transmitter carries its own unique code and is enrolled into the receiver's memory one at a time. That makes it considerably more secure than a dip-switch system, and it is why Mega Code became the standard on gated communities and commercial access installations.
This is the question to settle before you order anything. Linear built four incompatible formats and none of them cross over.
| Format | Frequency | How to identify it |
|---|---|---|
| Mega Code | 318 MHz | No dip switches. Programmed by pressing a learn button on the receiver. Part numbers start ACT, MDT, MT, MTS, MGT, MCT. |
| Delta 3 / DT | 310 MHz | 8 dip switches. Part numbers start DT, DNT. |
| Multi Code | 300 MHz | 10 dip switches. Part numbers 3089, 3070, 4120. |
| Alert | 303.875 & 315 MHz | 8 dip switches |
If your remote has dip switches, you are not on Mega Code. Count them: eight means Delta 3, ten means Multi Code. A 318 MHz Mega Code transmitter will not operate either, at any setting, and there is no adapter.
Mega Code transmitters come two ways, and mixing them up is the most common ordering mistake on this format.
Standard — each transmitter has a factory code. You enroll each one into the receiver individually. Fine for a house or a small site.
Block coded — the "B" suffix, as in ACT-31B or MDT-1B. Supplied in a sequential block of codes so a property manager can hand out remotes and enroll a whole range at once. This is what gated communities and apartment complexes run. If you are adding remotes to an existing block-coded system, you need the matching block — call us with the site details rather than ordering blind.
Custom coded — the "C" suffix. Made to a code range you specify. Ordered, not stocked.
| Model | Linear part | What it is |
|---|---|---|
| MTS1 | DNT00091 | 1-button visor transmitter. Replaces the MTR1. |
| MTS3 | DNT00093 | 3-channel visor transmitter. Replaces the MTR3. |
| MDT | DNT00052A | 1-channel visor transmitter |
| MDT-2 | DNT00053A | 2-channel |
| MDT-4 | DNT00054A | 4-channel |
| MDT-1B | ACP00721 | 1-channel, block coded |
| MDT-2B | ACP00720 | 2-channel, block coded |
| MDT-4B | ACP00722 | 5-channel, block coded |
| MT-1B | ACP00877 | 1-channel, block coded |
| MT-2B | ACP00746 | 2-channel, block coded |
| MGT | DNT00068 | Gate transmitter |
| MDT-MOD | DNT00087 | Personal body alarm transmitter |
The ACT range is the commercial and community side of Mega Code. The "H" suffix models carry an HID proximity inlay, so one credential works both the gate radio and a card reader at the door.
| Model | Linear part | What it is |
|---|---|---|
| ACT-31B | ACP00879 | 1-button, block coded |
| ACT-31D | ACP00954 | 1-button |
| ACT-31DH | ACP00957 | 1-button with HID proximity inlay |
| ACT-31DHC | ACP00959 | 1-button, HID inlay, custom coded |
| ACT-31C | ACP00939 | 1-button, custom coded — special order |
| ACT-34B | ACP00872 | 4-button, block coded |
| ACT-34D | ACP00955 | 4-button |
| ACT-34DH | ACP00958 | 4-button with HID inlay |
| ACT-34DHC | ACP00960 | Key-ring transmitter with HID inlay |
| ACT-34C | ACP00940 | 4-button, custom coded — lot of 10 |
| ACT-22B | ACP00616A | 2-button, block coded |
| Model | Linear part | What it is |
|---|---|---|
| AP5 | ACP00953 | 480-remote capacity. The one for a community gate. |
| MDR-U | DNR00100 | Universal receiver |
| MDR-2 | DNR00072 | 2-channel Mega receiver |
| MGR | DNR00104 | Gate receiver |
| MGR-2 | DNR00105 | 2-channel gate receiver |
| WOR | ACP00727 | Wiegand output receiver — feeds a radio credential into an access control panel |
| Kit | Contents |
|---|---|
| MDRU + 2× MTS1 | Receiver plus two 1-button remotes. The straightforward answer when there is no Mega Code radio on the opener at all. |
| MDRU + 2× MDT | Receiver plus two MDT remotes |
| Model | Linear part | What it is |
|---|---|---|
| NMTK | DNT00094 | Wireless keypad, 318 MHz, grey |
| MDKP | ACP00878 | Wireless keypad in steel housing |
| AM-DPR | ACP00961 | Proximity reader. Replaces the AM-PR. |
| AM-PT | ACP00742 | Proximity tags, lot of 25 |
| CLM125-H | — | Clamshell card, HID 125kHz proximity |
| Key | 222343 | Linear enclosure key |
Mega Code has been in production a long time and much of the early range is discontinued. If you are holding one of these numbers, order the replacement in the right-hand column.
| Old model | Linear part | Order instead |
|---|---|---|
| MTR1 | — | MTS1 |
| MTR3 | — | MTS3 |
| MCT / MCT-1 | DNT00083 | MTS1 |
| MCT-2 | DNT00084 | MDT-2 |
| MCT-3 | DNT00089 | MTS3 |
| MCT-11 | DNT00090 | MTS1 |
| ACT-21 | ACP00607 | ACT-31D |
| ACT-21B | ACP00615 | ACT-31B |
| ACT-22 | ACP00606A | ACT-22B |
| AM-PR proximity reader | ACP00740 | AM-DPR |
| MDTK keypad | DNT00058 | NMTK |
| MDRG / SMDRG gate receivers | DNR00073 / DNR00098 | MGR |
| MDR | DNR00071 | MDR-U |
There are no dip switches to match. Each transmitter is enrolled into the receiver's memory:
1. Find the learn or program button on the Mega Code receiver — on the opener, or in the gate control enclosure.
2. Press it once. An LED will change state to confirm the receiver is listening.
3. Press the button on the new transmitter you want to add.
4. The LED confirms the code is stored. Test the door or gate.
Each remote must be enrolled individually, and the receiver holds a fixed number — the AP5 takes 480, which is why it is the community-gate choice. If the receiver is full you have to erase and re-enroll, so on a large site keep a record of which code went to which resident.
Why does my new remote not work even though it's the right model? On Mega Code the model number is not enough — the transmitter has to be enrolled into the receiver. If enrolling doesn't take, the receiver's memory may be full.
What does the B suffix mean? Block coded. Ordered as a sequential range for a managed property. If you are adding to an existing block-coded system, tell us the site and we will match the block.
Can I mix Mega Code and Delta 3 on one gate? Only by fitting both receivers. The radios are on different frequencies and do not share.
My range has dropped. Check the antenna before replacing anything. An EXA-1000 or EXA-2000 kit gets the wire clear of the enclosure.
Will a universal remote work? The LiftMaster 374UT and 380UT cover some Mega Code systems, but they learn from a working remote. If nothing works any more, you need a genuine transmitter or a complete MDRU set.
Delta 3 / DT 310 MHz · Multi Code 300 MHz · Alert 303.875 & 315 MHz · Extended Range · all Linear remotes
Not sure what you have? Send a photo of the transmitter and the receiver to parts@gatehousesupplies.com, or call 866-965-5599. We have been supplying Linear since 1993.