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diff --git a/Documentation/serial/n_gsm.rst b/Documentation/serial/n_gsm.rst deleted file mode 100644 index f3ad9fd26408..000000000000 --- a/Documentation/serial/n_gsm.rst +++ /dev/null @@ -1,103 +0,0 @@ -============================== -GSM 0710 tty multiplexor HOWTO -============================== - -This line discipline implements the GSM 07.10 multiplexing protocol -detailed in the following 3GPP document: - - http://www.3gpp.org/ftp/Specs/archive/07_series/07.10/0710-720.zip - -This document give some hints on how to use this driver with GPRS and 3G -modems connected to a physical serial port. - -How to use it -------------- -1. initialize the modem in 0710 mux mode (usually AT+CMUX= command) through - its serial port. Depending on the modem used, you can pass more or less - parameters to this command, -2. switch the serial line to using the n_gsm line discipline by using - TIOCSETD ioctl, -3. configure the mux using GSMIOC_GETCONF / GSMIOC_SETCONF ioctl, - -Major parts of the initialization program : -(a good starting point is util-linux-ng/sys-utils/ldattach.c):: - - #include <linux/gsmmux.h> - #define N_GSM0710 21 /* GSM 0710 Mux */ - #define DEFAULT_SPEED B115200 - #define SERIAL_PORT /dev/ttyS0 - - int ldisc = N_GSM0710; - struct gsm_config c; - struct termios configuration; - - /* open the serial port connected to the modem */ - fd = open(SERIAL_PORT, O_RDWR | O_NOCTTY | O_NDELAY); - - /* configure the serial port : speed, flow control ... */ - - /* send the AT commands to switch the modem to CMUX mode - and check that it's successful (should return OK) */ - write(fd, "AT+CMUX=0\r", 10); - - /* experience showed that some modems need some time before - being able to answer to the first MUX packet so a delay - may be needed here in some case */ - sleep(3); - - /* use n_gsm line discipline */ - ioctl(fd, TIOCSETD, &ldisc); - - /* get n_gsm configuration */ - ioctl(fd, GSMIOC_GETCONF, &c); - /* we are initiator and need encoding 0 (basic) */ - c.initiator = 1; - c.encapsulation = 0; - /* our modem defaults to a maximum size of 127 bytes */ - c.mru = 127; - c.mtu = 127; - /* set the new configuration */ - ioctl(fd, GSMIOC_SETCONF, &c); - - /* and wait for ever to keep the line discipline enabled */ - daemon(0,0); - pause(); - -4. create the devices corresponding to the "virtual" serial ports (take care, - each modem has its configuration and some DLC have dedicated functions, - for example GPS), starting with minor 1 (DLC0 is reserved for the management - of the mux):: - - MAJOR=`cat /proc/devices |grep gsmtty | awk '{print $1}` - for i in `seq 1 4`; do - mknod /dev/ttygsm$i c $MAJOR $i - done - -5. use these devices as plain serial ports. - - for example, it's possible: - - - and to use gnokii to send / receive SMS on ttygsm1 - - to use ppp to establish a datalink on ttygsm2 - -6. first close all virtual ports before closing the physical port. - - Note that after closing the physical port the modem is still in multiplexing - mode. This may prevent a successful re-opening of the port later. To avoid - this situation either reset the modem if your hardware allows that or send - a disconnect command frame manually before initializing the multiplexing mode - for the second time. The byte sequence for the disconnect command frame is:: - - 0xf9, 0x03, 0xef, 0x03, 0xc3, 0x16, 0xf9. - -Additional Documentation ------------------------- -More practical details on the protocol and how it's supported by industrial -modems can be found in the following documents : - -- http://www.telit.com/module/infopool/download.php?id=616 -- http://www.u-blox.com/images/downloads/Product_Docs/LEON-G100-G200-MuxImplementation_ApplicationNote_%28GSM%20G1-CS-10002%29.pdf -- http://www.sierrawireless.com/Support/Downloads/AirPrime/WMP_Series/~/media/Support_Downloads/AirPrime/Application_notes/CMUX_Feature_Application_Note-Rev004.ashx -- http://wm.sim.com/sim/News/photo/2010721161442.pdf - -11-03-08 - Eric Bénard - <eric@eukrea.com> |