Optic Base Stations connect to your computer via USB, while connecting to the logger via an appropriate coupler.
There are 2 models:
Base-U-4
This model supports the following model loggers, and includes all relevant couplers
Base-U-1
This model is a lower price than the Base-U-4 and supports the UA (Pendant) series loggers only.
Note: Indoor dataloggers not listed above, have a direct USB connection and do not require a Base Station