IBM 6400 Setup Manual page 302

processing workstation in an interactive, batch data transfer, or distributed
data processing environment (for example, an LU for an application program
that uses CICS/VS and communicates with an IBM 6670 Information
Distributor); or (2) logical units in peripheral nodes (for example, two
6670's) that communicate with each other. The data stream is the SNA
Character String (SCS) for data processing environments and Office
Information Interchange (OII) Level 2 (a precursor of DCA) for word
processing environments.
LU type 6.1
An LU type 6.1 is for an application subsystem that communicates with
another application subsystem in a distributed data processing environment.
An example of an LU type 6.1 is an application program that uses CICS/VS
and communicates with an application program that uses IMS/VS.
LU type 6.2
An LU type 6.2 supports sessions between two applications in a distributed
data processing environment. The data stream is either the SNA General
Data Stream (GDS), which is a structure–field data stream, or a user–defined
data stream. LU 6.2 session provide communication between (1) two PU
type 5 nodes (host resource–owning VTAM), (2) a PU type 5 node and a PU
type 2.1 node, and (3) two PU type 2.1 nodes. Examples (1)
VTAM–to–VTAM communication, or an application program that uses
CICS/VS and communicates with another application program that uses
CICS/VS, (2) An application program which uses VTAM and PSF/MVS
communicating with an IBM 3820, 3935, or PSF/2; or (3) Two AS/400's
communicating in APPC mode.
LU type 7
An LU type 7 is for an application program and a single display workstation
in an interactive environment. An example of an LU type 7 is an application
program in an AS/400 communicating with a 5250–type terminal. The data
stream is the 5250 data stream.
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