Miscellaneous Electronics
4 Port Serial Device Server, 2 Port 10/100 RJ45 Ethernet - 4 Port DB9 RS232 & 5.08mm Terminals RS485/RS422 Serial Converter, Support TCP/IP/DHCP/DNS/HTTP
Carefully designed watchdog circuit, 24 hours without downtime and stable With protective design, anti-surge 4KV (8 / 20US), pulse group is 1.5KV 100KHZ 4 serial server, 4 channel 232 485 422, can be combined in any way and more stable Wide voltage...
https://www.bizrate.co.uk/miscellaneouselectronics/4-port-serial-device-server-oid16731698791.html