LinuxQuestions.org - Minicom

I have a router with linux firmware and attached to it a USB modem with which I can do both data and voice.

If I send ATD<number>; trough Minicom the call starts normaly, but if I send

Code:

echo -e "ATDT<number>;\r\n" > /dev/usb/tts/2

I get

Code:

ATDT<number>;

OK



^ORIG:1,0



^CEND:1,0,29,16

which means the command has been executed successfully but is immediately terminated normally. Any other command send through echo method works ok. I was able to send SMS, edit phonebook and many many other stuff, but not make a call.
So what is different from sending the call command within Minicom 2.5 and echo it?