... system and security alarm management system. Parameter List Parameter Single Access Control BoardTwo-door Access Control Board Four-Door Access ... ty of computer serial prot or q ' ty of 485hub port, support 256pcs ports Operation Temperature - 40 C~70 C ... coverage area Collocations PCB board, case, power, power line, serial port communication line, software, manual, certificate, key(2pcs), carton Alarm ...