^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) ==============================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) GSM 0710 tty multiplexor HOWTO
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) ==============================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) This line discipline implements the GSM 07.10 multiplexing protocol
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) detailed in the following 3GPP document:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) https://www.3gpp.org/ftp/Specs/archive/07_series/07.10/0710-720.zip
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) This document give some hints on how to use this driver with GPRS and 3G
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) modems connected to a physical serial port.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) How to use it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) -------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 1. initialize the modem in 0710 mux mode (usually AT+CMUX= command) through
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) its serial port. Depending on the modem used, you can pass more or less
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) parameters to this command,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) 2. switch the serial line to using the n_gsm line discipline by using
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) TIOCSETD ioctl,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) 3. configure the mux using GSMIOC_GETCONF / GSMIOC_SETCONF ioctl,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 4. obtain base gsmtty number for the used serial port,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) Major parts of the initialization program :
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) (a good starting point is util-linux-ng/sys-utils/ldattach.c)::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) #include <stdio.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) #include <stdint.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) #include <linux/gsmmux.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) #include <linux/tty.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) #define DEFAULT_SPEED B115200
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) #define SERIAL_PORT /dev/ttyS0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) int ldisc = N_GSM0710;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) struct gsm_config c;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) struct termios configuration;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) uint32_t first;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) /* open the serial port connected to the modem */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) fd = open(SERIAL_PORT, O_RDWR | O_NOCTTY | O_NDELAY);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) /* configure the serial port : speed, flow control ... */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) /* send the AT commands to switch the modem to CMUX mode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) and check that it's successful (should return OK) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) write(fd, "AT+CMUX=0\r", 10);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) /* experience showed that some modems need some time before
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) being able to answer to the first MUX packet so a delay
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) may be needed here in some case */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) sleep(3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) /* use n_gsm line discipline */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) ioctl(fd, TIOCSETD, &ldisc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) /* get n_gsm configuration */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) ioctl(fd, GSMIOC_GETCONF, &c);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) /* we are initiator and need encoding 0 (basic) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) c.initiator = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) c.encapsulation = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) /* our modem defaults to a maximum size of 127 bytes */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) c.mru = 127;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) c.mtu = 127;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) /* set the new configuration */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) ioctl(fd, GSMIOC_SETCONF, &c);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) /* get first gsmtty device node */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) ioctl(fd, GSMIOC_GETFIRST, &first);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) printf("first muxed line: /dev/gsmtty%i\n", first);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) /* and wait for ever to keep the line discipline enabled */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) daemon(0,0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) pause();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) 5. use these devices as plain serial ports.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) for example, it's possible:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) - and to use gnokii to send / receive SMS on ttygsm1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) - to use ppp to establish a datalink on ttygsm2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) 6. first close all virtual ports before closing the physical port.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) Note that after closing the physical port the modem is still in multiplexing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) mode. This may prevent a successful re-opening of the port later. To avoid
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) this situation either reset the modem if your hardware allows that or send
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) a disconnect command frame manually before initializing the multiplexing mode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) for the second time. The byte sequence for the disconnect command frame is::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) 0xf9, 0x03, 0xef, 0x03, 0xc3, 0x16, 0xf9.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) Additional Documentation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) ------------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) More practical details on the protocol and how it's supported by industrial
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) modems can be found in the following documents :
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) - http://www.telit.com/module/infopool/download.php?id=616
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) - http://www.u-blox.com/images/downloads/Product_Docs/LEON-G100-G200-MuxImplementation_ApplicationNote_%28GSM%20G1-CS-10002%29.pdf
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) - http://www.sierrawireless.com/Support/Downloads/AirPrime/WMP_Series/~/media/Support_Downloads/AirPrime/Application_notes/CMUX_Feature_Application_Note-Rev004.ashx
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) - http://wm.sim.com/sim/News/photo/2010721161442.pdf
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 11-03-08 - Eric Bénard - <eric@eukrea.com>
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
3 Commits
0 Branches
0 Tags