Envoy ACP/XF Application Programming Manual

Features Common to Bit-Synchronous Protocols
EnvoyACP/XF Application Programming Manual–132179
B-12
U-Frame Responses
U-Frame Responses
U-frame responses are categorized according to function:
Responses to Mode-Setting Commands and Status Requests
The secondary/combined station transmits the UA, DM, and RIM responses to request a
mode-setting command or to respond to a mode-setting command from the
primary/combined station. DM and RIM also indicate the secondary/combined station
status.
UA
The secondary/combined station transmits the unnumbered acknowledgment (UA)
response to acknowledge the receipt and acceptance of the SNRM, SABM, SNRME,
SABME, SIM, DISC, and RSET unnumbered commands.
The unnumbered command directs the UA response transmission in the standard one
octet or extended-control field format. The UA response does not allow an information
field.
EnvoyACP/XF automatically transmits UA, as appropriate. Your application also can
explicitly direct EnvoyACP/XF to transmit a UA response by specifying the appropriate
value in the first byte of the MCW for that procedure call.
DM
The secondary/combined station transmits a disconnect mode (DM) response to report
that the station is in a logically disconnected state.
Your application cannot transmit DM. EnvoyACP/XF transmits DM automatically.
RIM
The secondary/combined station a request initialization mode (RIM) response to request
a SIM (set initialization mode) command.
U-Frame Responses Category Responses
Responses to mode-setting
commands and status requests
UA, DM, RIM
Responses to information-
transfer commands
UI
Responses to recovery
commands
FRMR
Responses to other commands XID, RD
Responses to nonreserved
Commands
Nonreserved 0-3