In light of previous reviews, as soon as I opened the box I stuck each one into a breadboard and ran a basic test. I can't say if they meet all specs, but they work in the main modes, at least at close range, with no visible differences from other comparable modules purchased in the past. Also, all the boards I received had QFN ICs on board, none of the epoxy blobs that anyone has supposedly gotten in the past. This allowed me to graft one of the chips onto a custom PCB using a hot air tool, where it worked well.
π Gigabit Ethernet Media Converter, Single Mode Dual SC Fiber, 1000Base-LX to 10/100/1000Base-Tx, up to 20km, 2-Pack
9 Review
π SFP Copper RJ45 Transceiver Gigabit Module 1000Base-T Compatible: Cisco GLC-T/SFP-GE-T, Meraki MA-SFP-1GB-TX, Mikrotik, Ubiquiti, Netgear, D-Link, TP-Link, Broadcom - 100 Reach, 2 Pack
8 Review
π Ximimark 1Pcs ESP8266 Network Relay WIFI Module 220V 10A DC 7-30V 4 Layers Board TVS Input Automatic Protection: Enhanced Home Automation Solution
8 Review
π‘ Izokee ESP-01 Serial WiFi Transceiver Module with USB Converter, Compatible with Arduino
8 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 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