GT864-3G Terminal Product Description
80269ST10071a Rev.0 - 14/09/0
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page 27 of 41
3.2 CMUX
CMUX (Converter-Multiplexer) is a multiplexing protocol implemented in the Telit module that can
be used to send any data, SMS, fax, TCP data.
3.2.1
Product architecture
The Multiplexer mode enables one serial interface to transmit data to four different customer
applications. This is achieved by providing four virtual channels using a Multiplexer (Mux).
This is especially advantageous when a fax/data/GPRS call is ongoing. Using the Multiplexer
features, e.g. controlling the module or using the SMS service can be done via the additional
channels without disturbing the data flow; access to the second UART is not necessary.
Furthermore, several accesses to the module can be created with the Multiplexer. This is of great
advantage when several independent electronic devices or interfaces are used.
To access the three virtual interfaces, both the GSM engine and the customer application must
contain Mux components, which communicate over the multiplexer protocol.
In Multiplexer mode, AT commands and data are encapsulated into packets. Each packet has
channel identification and may vary in length.
3.2.2
Implementation feature and limitation
•
7.10 CMUX Basic Option used
•
CMUX implementation support four full DLCI (Serial Port)
•
Every CMUX instance has its own user profile storage in NVM
•
Independent setting of unsolicited message.
•
Every CMUX instance has its own independent flow control
NOTE
: More details about the Multiplexer mode are available in the Cmux Product Specification
