Devices work as advertised, they split the ethernet port into two separate cables as four wires are not typically used for 100 megabit connections. If you need a gigabit connection, you're out of luck as it uses all eight wires. In that case, you'd be better off getting two inexpensive managed switches that support VLANs and configuring them to isolate your networks.
π ASUS USB-BT400 USB Bluetooth Dongle Receiver - Compatible with Laptops and PCs, Plug and Play for Windows 10/8/7/XP. Supports Printers, Phones, Headsets, Speakers, Keyboards, and Controllers in Black.
79 Review
Enhance Your WiFi Range with TP-Link TL-WPA4220KIT 300Mbps AV500 Powerline WiFi Extender Start Kit
37 Review
Enhance Internet Speed with TP-Link AC1200 Wireless Dual Band USB Adapter (Archer T4U V1)
40 Review
High Gain Wireless Network Adapter - TP-Link Nano USB Wifi Dongle with 150Mbps Speed for PC Desktops and Laptops. Compatible with Win10/8.1/8/7/XP Linux 2.6.18-4.4.3, Mac OS 10.9-10.15 (TL-WN722N)
46 Review
π StarTech.com NETRS232 Serial to IP Ethernet Device Server - DIN Rail Mountable - Serial Device Server - Serial Over IP Device Server (Black)
4 Review
π uni USB C Hub with Ethernet Adapter, 4K HDMI, Gigabit Ethernet, and 3 USB 3.0 Ports for MacBook Pro, iPad Pro, XPS
11 Review
HB-UMLS Sabrent USB 2.0 Hub with 4 Ports and LED Power Switches for Each Port
12 Review
π USR-TCP232-410s: RS232/RS485 Serial to Ethernet Adapter/IP Device Server with DHCP/DNS Support
4 Review