Wire an LP1502 Door Controller (ADC-AC-LP1502) to an Access Control expansion board
The serial I/O device communication port (TB3) can support up to 16 Alarm.com expansion modules using a 2-wire RS-485 bus. The maximum cable length is 4,000 feet (1,219 m). When powering expansion modules and peripherals from the ADC-AC-LP1502, be cautious not to exceed 650 mA @ 12V DC. 22 AWG minimum is recommended for readers.
Important: Each expansion module must also be wired for power (VIN to + 12VDC / GND to - 12VDC).
Expansion board wiring
Up to 16 total expansion modules may be wired. The last expansion module on the bus must have jumper J4 installed for ADC-MR52 modules and J601 for the MR50-S3 or J1 for the MR50-S2.
Use twisted pair 24 AWG, 120 OHM impedance cable with drain and shield wires. 4,000 ft. (1,219m) maximum total length.
