... interface, linear output,Audio OutputBuilt-in Audio I/O portAudio two-way talkTCP, UDP, IP, HTTP, FTP, SMTP, DHCP, DNS,ARP, ICMP ... Interface1 RS485 port,1 RS232 port (supports transparent protocols)1channel on/off input, supporting NO (normally open) or NC (normally close ... ) sense.Alarm Input 1 channel on/off output,120VAC 1A/24VDC 1AAlarm Output DC 12V,1AInput ...