SIM800 Series_Multiplexer_Application Note_V1.04
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3.2.3 DISC
DISC is command frame and shall be used to close down DLC. Prior to acting the command, the receiving
station shall confirm the acceptance of the DISC command by the transmission of a UA response. Please
see the diagram above and refer to 3.6 for more details.
3.2.4 DM
The DM response frame shall be used to report a status whether the station is logically disconnected from
the data link. When in disconnected mode no commands are accepted until the disconnected mode is
terminated by the receipt of a SABM command. If a DISC command is received while in disconnected mode
a DM response should be sent. Please refer to 3.1 for more details.
3.2.5 UIH
The UIH command/response shall be used to send user data at either station. Please refer to 3.2 for more
details.
3.2.6 UI
Not support.
3.3 DLC Establishment
The establishment of a DLC will be initiated by the TE.
TE wishing to establish a DLC transmits a SABM frame with the P-bit set to 1. The address field contains
the DLCI value associated with the desired connection. If MS is ready to establish the connection it will reply
with a UA frame with the F-bit set to 1. If MS is not ready or unwilling to establish the particular DLC it will
