Rainbow Electronics GC864-PY - Manual (Page 31)

Telit GE864 and GC864 Product Description
80273ST10008a Rev. 14 - 18/09/08
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 31 of 62
4.4 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.
4.4.1 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.
4.4.2 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.
• In case of GPS product one serial port can be dedicated to NMEA output.
• Every CMUX instance has its own independent flow control
NOTE: More details about the Multiplexer mode are available in the Cmux User Guide.