CMUX/en
Modem operation in CMUX mode is an experimental function and may not work "out of the box". Performance is not guaranteed.
he modem supports multiplexing mode - creating virtual ports through which you can simultaneously work with the modem. For example, through one port you can open a PPP session for GPRS, and through another you can receive and send SMS, check the balance, etc.
You need the GSM line discipline to be supportred in the kernel (included as a module in the standard firmware). A special daemon cmux sends the modem into CMUX mode, then creates four virtual ports, /dev/ttyGSM[1-4] . The closure of the demon cmux to close all virtual ports will lead to a kernel panic!
Daemon cmux
Оригинальный автор: [1]
Демон установлен по-умолчанию как "/usr/bin/cmux", доступен в пакете cmux. Скачать бинарник демона можно здесь
Пример работы
Включаем модем:
root@wirenboard:~# wb-gsm on
Запускаем демон cmux:
root@wirenboard:~# cmux SERIAL_PORT = /dev/ttyAPP0 AAAT : AAAT OK AT+IFC=2: AT+IFC=2,2 OK AT+GMM : AT+GMM SIMCOM_SIM900R OK AT : AT OK AT+CMUX=: AT+CMUX=0 OK Line dicipline set Created /dev/ttyGSM1 Created /dev/ttyGSM2 Created /dev/ttyGSM3 Created /dev/ttyGSM4 Going to background
Теперь общение с модемом можно производить в любом из каналов /dev/ttyGSMx