Pu

In the IBM Systems Network Architecture (SNA), a device that manages the communications hardware and software, participating in the controlling and routing of network communications. All physical devices are assigned a PU Type (1, 2, 3, or 5) that identifies the level of the device (terminal, controller, communications processor, or host node) and its origin (IBM/SNA or non-IBM/SNA). See also hardware, SNA, and software.