How can i run At-commadns with the ADB?

I'm new here. i hope you guys could help me. i try to communicate with the modem of my samsung galexy S3 GT-I9300 over the ADB tool. My galexy is rooted and is accessible through adb. Now i wanna execute AT-commands over the adb-tool. i already tried a few AT-commands but the modem doesn't wanna response.

1. First of all i was running "cat /proc/tty/drivers" to get the right driver. my output:

**

root@m0:/ # cat /proc/tty/drivers



/dev/tty /dev/tty 5 0 system:/dev/tty

/dev/console /dev/console 5 1 system:console

/dev/ptmx /dev/ptmx 5 2 system

/dev/vc/0 /dev/vc/0 4 0 system:vtmaster

rfcomm /dev/rfcomm 216 0-255 serial

g_serial /dev/ttyGS 250 0-3 serial

usbserial /dev/ttyUSB 188 0-253 serial

s3c2410_serial /dev/ttySAC 204 64-67 serial

serial /dev/ttyS 4 64-67 serial

pty_slave /dev/pts 136 0-1048575 pty:slave

pty_master /dev/ptm 128 0-1048575 pty:master

unknown /dev/tty 4 1-63 console





2. Consequenzly my driver adress is "/dev/ttyGS0" soo: i run the next command "echo -e "AT\r" > /dev/ttyGS0" but the modem is not responding and nothing happens:

root@m0:/ # echo -e "AT\r" > /dev/ttyGS0

root@m0:/ #



3. soo i quit the tool and trie another command "service check phone":



130|root@m0:/ # service check phone

Service phone: found

root@m0:/ #



it looks like he at least found a kind of a modem.

4. soo i google a bit longer and i find the nice tool called microcom, which is includet in busybox. i installed busybox! and trie to run: "busybox microcom -t 5000 /dev/ttyGS0" but output:



root@m0:/ # busybox microcom -t 5000 /dev/ttyGS0

microcom: applet not found

1|root@m0:/ #









I really hope you can help me to find my problem with my code oder better speaking my commands.