User`s guide

38 DC 900-1317J
ADCCP NRM Programmer’s Guide
OPTION 8 This option forbids the use of information response frames. This
implies that a secondary station cannot send information frames to its
primary station. This option is normally used during ABM operation,
in which combined stations always send I-frames as command
frames.
OPTION 9 This option forbids the use of information command frames. This
implies that a primary station cannot send information frames to any
secondary stations.
OPTION 10 This option defines an extended control field that supports modulo
128 sequence numbers. This allows the link to send up to 127 (instead
of 7) I-frames before requiring acknowledgment.
OPTION 11 This option forbids the use of the reset (RSET) command in ABM
operation. This removes the ability to reset send and receive variables
associated with only one direction of information flow. This option
does not apply to NRM or ARM operation (in which the RSET com-
mand does not exist), but is normally used in ABM operation.
2.8 Summary of Frame Types
ADCCP defines a command frame as any frame sent by the primary station to a second-
ary station. A response frame is any frame sent by a secondary station to its primary sta-
tion. In balanced configurations, the same definition holds true for frames exchanged
between the primary and secondary functions within different combined stations.
Ta ble 2 –1 summarizes these frame types.
2.9 Summary of NRM, ARM, and ABM
The three operational modes (NRM, ARM, and ABM) mentioned in Section 2.1 and
Section 2.2 may be viewed as three overlapping sets of link operation rules as shown in