Multiplexer User's Guide
Confidential / Released
s
mobile
2 Multiplexer protocol – an overview
2.1 Product concept and architecture
The multiplexer mode enables one serial interface to transmit data to three different custo- mer applications. This is achieved by providing three 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 a channel identification and may vary in length.
Note:
All statements regarding GPRS are valid only for Siemens wireless products capable of GPRS.
Terminal programs or internal programs integrated in cus- tomer application platform
User application
GSM engine
Terminal 1
Terminal 2
Terminal 3
Channel 1
Channel 2
Channel 3
MUX conforming to GSM 07.10
Serial
I/O
MP
Serial
I/O
MUX conforming to GSM 07.10
1
2
3
Data/Fax/
GPRS supported
Data/Fax not supported
Figure 1: Multiplexer architecture
Mux_guide_v06 | Page 9 of 36 | 30.06.2004 |