
They are cheap and do the job but have a very high bounce rate over time. We used about 40 of them and about 25% of them failed within a year.

π‘ Izokee ESP-01 Serial WiFi Transceiver Module with USB Converter, Compatible with Arduino
8 Review

10GBase-T SFP+ Transceivers, 10G Copper RJ-45 SFP+ CAT.6a, up to 30 meters, π Cisco SFP-10G-T-S Compatible, Ubiquiti UniFi UF-RJ45-10G Supported, Fortinet, Netgear, D-Link, Supermicro (Pack of 2)
9 Review

TRENDnet TC-TP1 Network Signal Testing Probe with Adjustable Volume, Speaker and Compatibility for TC-NT2
8 Review

MikroTik S+RJ10 Ethernet Transceiver
10 Review

π StarTech.com NETRS2321P: 1-Port RS232 to Ethernet IP Converter, Serial over IP Device Server - Black
5 Review

HB-UMLS Sabrent USB 2.0 Hub with 4 Ports and LED Power Switches for Each Port
12 Review

π CERRXIAN RS232 to Ethernet Serial Device Server - TCP/IP Converter with 1Port DB9 RS232 Serial to Ethernet Connectivity
3 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