Works well, arrived quickly, prices comparable to places like ebay. The blocks have no pin markings, not even grounds, and I don't see any documentation, so you'll have to spend time looking up pinouts online. Luckily, these devices seem to share a common layout, so the internet has your back.
π‘ Izokee ESP-01 Serial WiFi Transceiver Module with USB Converter, Compatible with Arduino
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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
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)
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MikroTik S+RJ10 Ethernet Transceiver
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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
UGREEN USB 3.0 Ethernet Adapter Hub with RJ45: Fast Gigabit Ethernet Converter, 3 Ports USB 3.0 Hub Compatible for MacBook, iMac, Surface Pro, Chromebook, Laptop, PC
11 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