The Linear ACT-34B is a gate remote. product page: http://www.linearcorp.com/product_detail.php?productId=867 manual: http://www.linearcorp.com/pdf/manuals/ACT-31B_ACT-34B.pdf FCCID: EF4ACP00872 The Linear ACT-31B is the same than the ACT-34B, but have only one button instead of four.

The Monarch 318LIPW1K(-L) is a compatible/clone of the Linear ACT-31B. product page: http://www.communitycontrols.com/Product/?PID=196 manual: http://s3.amazonaws.com/CommunityControls/PDFs/CC-Monarch-318LIPw1K.pdf FCCID: SU7318LIPW1K

megacode

The value is encoded using Linear LLC MegaCode scheme. It uses AM/ASK/A1D pulse position for the radio signal.

The radio transmission uses the 318MHz frenquency. The signal is encoded using Linear LLC MegaCode scheme. It uses AM/ASK/A1D pulse position for the radio signal. 24 bits are transmitted:

• 1 sync bit
• 16 bits for the remote code
• 4 bits for the facility code
• 3 bits for data bits (the channel/button used)

24 bursts are transmitted, plus 1 blank burst, within 150 ms. Each burst is a 6 ms bitframe. Withing the burst there is a 1 ms pulse after 2 or 5 ms. The blank burst does not include a pluse and is used to separate transmissions. The first pulse is used to synchronize and is alwasy after 5ms within the burst.

sdr

This folder contains tools to be used with Software Defined Radio (SDR).

A RTL-SDR has been used to capture the signal. Use sdrangelove to figure out the frequency. It is around 318MHz, but +/- 100kHz. Use rtl_fm to record the transmission: rtl_fm -f 317.962M -M am megacode.pcm A few remote transmissions have been captured and the recordings are saved in samples

megacode.pcm will have signed 16 bits little endian sample, at 24000Hz. Use decode.rb to decode this recording: ./decode.rb megacode.pcm

To record is an opprotunistic way (someone uses an unknown remote further away), you have to tweak rtl_fm: rtl_fm -f 317.9M:318.1M:20k -g 10 -l 700 -M am megacode.pcm

pic

This folder contains firmwares for the transmitter and receiver microcontrollers.

The PCB of the ACT-31B is the same than the ACT-34B, with only one switch out of four populated. It uses a PIC12C508A (SM package) microcontroller. This microcontroller is EEPROM based (designated by the 'C' in the name) which the PICkit 2 can't program. It is programmed using the test points, but only once since it's a One Time Programmable (OTP) chip.

A pin compatible flash based chip can be used instead. Most P12FXXX are, like the PIC12F629/PIC12F675 (simplest alternative), PIC12F617 (more flash but no EEPROM), and PIC12F1840 (high end). They come in SN packages, which is thiner then the original SM package. But the pitch is the same and the pins can be soldered on the pads.

The 318LIPW1K uses a re-programmable chip (flash based). It uses a PIC12F629 (SN package) microcontroller. Monarch also adversitve that the code is programmable. I could not find the software. The programming header is even present on the board. But the microcontroller has read protection enabled.