cour_write
cour_write(FD, num, strlen(num));
cour_write(FD, "\r", 1);
cour_write(FD, "\r", 1); /* send anything to abort the call */
cour_write(FD, "\rAT Z\r", 6); /* reset modem */
cour_write(FD, "+++", 3);
cour_write(FD, "\rAT Z\r", 6);
static void cour_write(int, char *, int);
cour_write(FD, "AT E0\r", 6); /* turn off echoing */
cour_write(FD, "AT C1 E0 H0 Q0 X6 V1\r", 21);
cour_write(FD, "AT D", 4);