UMTS/HSPA Module Series
UC15 MUX User Guide
UC15_MUX_User_Guide Confidential / Released 15 / 35
4.2.4. 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.
4.2.5. UIH
The UIH command/response shall be used to send user data at either station.
4.3. Control Channel
At the initiation of communication between the TE and UE, a control channel is set up with DLCI 0. This
channel is used to convey information between the two multiplexers.
4.3.1. Message Format
Multiplexer control channel is the basic channel which is used to establish DLC, launch power saving,
wake up from power saving and implement flow control mechanism.
Control channel is the first channel established at the initiation of the multiplexer between the TE and MS
and it has the DLCI value 0.
UIH message frame is transmitted through control channel. All UIH message frames conform to the
following format.
Type
Length
Value 1
Value 2
……
Value n
Each box in the table represents a field of minimum size in one octet.
The first type field octet has the following format:
1
2
3
4
5
6
7
8
EA
C/R
T1
T2
T3
T4
T5
T6
The EA bit is an extension bit. It is set to 1 in the last octet of the sequence. In other octets, EA is set to 0.
Quectel multiplexer only supports to transmit one octet. So EA is always set to 1.
Quectel
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