Sinilink MODBUS Interface Module (XY-WFPOW)
Sinilink MODBUS Interface

Available from:

Install method:
USB to Serial

GPIO #Component
GPIO00 None
GPIO01 ???
GPIO02 LedLink
GPIO03 ???
GPIO04 Button 1
GPIO05 None
GPIO09 None
GPIO10 None
GPIO12 None
GPIO13 None
GPIO14 None
GPIO15 None
GPIO16 None
GPIO17 None

In order to add MODBUS functionality you will need to compile your own Tasmota build with USE_MODBUS_BRIDGE enabled (maybe USE_MODBUS_BRIDGE_TCP as well, depending on your needs)

It is possible to use solid core 24 AWG wires to make the connection without needing to solder them to the Sinilink board, but they may need soldering to a connector for the USB to serial adapter. Alternatively, you can strip some Ethernet Cat5e cable, which has the perfect diameter to fit in this board without soldering.