I have a 3G modem on my BeagleBone Linux system that supports GSM0710 multiplexing (i.e. can create >= 2 virtual serial ports that connect to the physical modem port, which can then be used to run ppp on one, and AT commands the other).
I'm trying to use the ldattach command to get this to work, as described in https://www.kernel.org/doc/Documentation/serial/n_gsm.txt.
So I run these commands as root:
ldattach -d GSM0710 /dev/ttyO2 ldattach: opened /dev/ttyO2 ldattach: set to raw 0 ---: cflag=0x1cb2 ldattach: line discipline set to 21
Then create some virtual serial devices with:
MAJOR=`cat /proc/devices |grep gsmtty | awk '{print $1}` for i in `seq 1 4`; do mknod /dev/ttygsm$i c $MAJOR $i done
However, when I try to connect to one of the /dev/ttygsm ports, I always get this error "can't open /dev/ttygsm1: Level 2 halted".
Does anyone know what this error means, and how to get the above muxing scheme to work?
Thanks, Fred
grep gsmtty | awk '{print $1}
can be shortened toawk '/gsmtty/{print $1}
.