I have downloaded a small app called ZTerm that is something like a terminal window to access the modem.

One very interesting thing I noticed now:

As I open the ZTerm app and another regular Terminal, each window side by side, and I type on the regular terminal window:

# echo "ATDT0," > /dev/cu.modem

and hit enter

The "ATDT0," appears on the ZTerm window. That means that my device is "listening" to my echo command. Right?

As I go back to ZTerm window, and hit enter, I mean just enter, not the entire command line, the modem dials "zero".

I think my dificulty is to include the enter in the "ATDT0," string, using the regular terminal window.

I tried (on the regular terminal window) placing a "\" just after the comma, and including an "enter" in the string, but this only caused the carrier to move one line down in the ZTerm window.

I guess I can do it once I can input the "enter" in the modem string.

Any clues?