This invention provides a brewing head unit of a coffee machine for inserting and locking the filter and the filter holder into the brewing head of a coffee machine. The encrypted data is then decrypted at the security appliance, wherein at least a portion of the decrypted data is re-encrypted according to a second encryption protocol at the security appliance. The ability to predict such properties has numerous advantages. In one embodiment, a gateway determines interworking information that is needed to interwork an H. A drain passage is formed in the injector body, in fluid communication with the actuator bore.