TwinCAT 3.1 offers an option to manage TwinCAT software licenses via the EtherCAT Terminal EL6070. The EL6070 embodies the hardware license key in the modular EtherCAT I/O system. Data transfer takes place via EtherCAT.

The EL6070 license key terminal is equipped with a local data memory for saving TwinCAT 3.1 license files. It is accessed via TwinCAT 3.1. The functionally equivalent C9900-L100 license key USB stick also features this data memory.

Both the EtherCAT terminal and the USB stick are available with factory pre-installed licenses: EL6070-0033, C9900-L100-0033.

Note that the EL6070 and EL6070-0033 are two different devices in terms of EtherCAT and are therefore not interchangeable in the EtherCAT I/O configuration.

https://www.beckhoff.com/vi-vn/products/i-o/ethercat-terminals/el6xxx-communication/el6070.html