... ---Remark: N denotes q ' ty of computer serial prot or q ' ty of 485hub port, support 256pcs portsOperation Temperature- ... ControllersRS232: Communication Distance less than 13m, suggestion distance is 3m or less RS485: bus line max length 1200m, suggestion length ... , is able to alarm by hardware, if connected with strengthened expansion board, then is able to Security alarm Single Door RS485 Network ...