The TCPADB5100 adapter board is intended to be used with the Wiznet WIZ810MJ Ethernet module. This module uses the W5100 Ethernet chip. The WIZ810MJ module can be used in bus and SPI mode. I2C mode is not supported by the W5100.
The TCPADB5100 adapter board will put the WIZ810MJ into SPI mode. It has an optional voltage stabilizer and all the pins are reduced to the necessary pins which are available on a pin header. You can use this PCB on a breadboard.
All BASCOM-AVR TCP/IP commands are supported. You need BASCOM-AVR version 2075 which includes the W5100 library