This is an eVLBI control parameter. Be warned: eVLBI support is under development. The eVLBI parameters are GRABTO, GRABTIME, GRABGAP, and DATAPATH.
DATAPATH determines where the main data flow goes. It is meant to be used with systems like Mark5 that have an eVLBI (over the net) capability. The data can either go to disk as in normal observing DATAPATH=IN2DISK or it can go directly to the network DATAPATH=IN2NET.
When the data are sent to disk, there is an option to send small amounts over the network later for fringe checks and the like. That option is controlled by the GRAB... parameters.