User`s guide

2: ADCCP NRM Protocol Summary
DC 900-1317J 37
(or function) to issue a disconnect (DISC) command. This option is
not normally used in ARM or ABM operation, but may be used in
NRM operation in a multidrop unbalanced configuration.
OPTION 2 This option improves error recovery by defining a reject (REJ) super-
visory command/response frame that reports sequence number
errors. An REJ response triggers sequential retransmission of infor-
mation frames, beginning with the lost frame.
OPTION 3 This option refines option 2 recovery procedures by defining a selec-
tive reject (SREJ) supervisory command/response frame that triggers
retransmission of the missing frame only.
OPTION 4 This option supports exchange of unnumbered information frames
by defining unnumbered information (UI) command/response
frames. Data exchanged via UI frames is not acknowledged and is
therefore unprotected from data loss. No error recovery procedures
exist for UI frames.
OPTION 5 This option provides support for the optional initialization state by
defining SIM command frames and RIM response frames. Initializa-
tion mode is set as a result of an SIM/UA exchange initiated by the
primary station. The secondary station may request the primary sta-
tion to set initialization mode by transmitting the RIM response.
OPTION 6 This option defines the unnumbered poll (UP) command to support
unnumbered polling. The primary station transmits UP command
frames to invite the secondary station to transmit information. Unlike
a polling receive ready (RR) command frame, the UP command
frame does not acknowledge previous transmissions.
OPTION 7 This option defines a recursively expandable address field to allow
frame addressing to exceed the normal size of one octet.