Envoy ACP/XF Application Programming Manual

EnvoyACP/XF and the Application Task
EnvoyACP/XF Application Programming Manual–132179
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Definition of Station
READ[X]
SETMODE[NOWAIT]
WRITE[X]
WRITEREAD[X}
For further information on how you can use these file-system procedures with
EnvoyACP/XF, see Section 4, System Procedure Call Specifics for EnvoyACP/XF
.
Definition of Station
The ADCCP protocol standard defines “station” as a method of data link control.
Methods of control include primary link control functions, secondary link control
functions or a combination of both primary and secondary link control functions. These
three functionalities are called the:
•
Primary station
•
Secondary station
•
Combined station
In this manual, the term “station” refers to a logical entity, that is, to the function
provided by the physical entity. For example, if a physical station in a network performs
primary data link control functions it is called the “primary station.” A physical station
can contain one or more logical stations.
Primary Station
A primary station has only a primary link control capability. The primary station
transmits command frames (commands) to one or more secondary stations on the link.
The primary station receives responses from the secondary station or stations and the
primary station maintains a separate information transmitting ability or information
receiving ability, or both, with each secondary station on the link.
Secondary Station
A secondary station has only a secondary link control capability. The secondary station
transmits response frames (responses) to the primary station. The secondary station
receives command frames from the primary station and maintains one information
transmitting ability or one information receiving ability, or both, with the primary
station.
Combined Station
A combined station has balanced link control capability. The combined station transmits
both command frames (commands) and response frames (responses) to another
combined station. A combined station receives both commands and responses from
another combined station and maintains one information transmitting ability to and one
information receiving ability from the other combined station.