dtr - DTR on/off for sys3/sys5
Brandon S. Allbery
allbery at ncoast.UUCP
Fri May 16 08:22:17 AEST 1986
The following program (NOT shar'ed!) is a utility to set/reset DTR on a serial
port. Usage is ``dtr [+-]ttyxx''. + turns it on, - turns it off.
It's useful for telling a modem not to answer the phone after disabling a
dialin line (I have a shell script which does this automatically).
Cut and enjoy.
--Brandon
------------------------------- cut here ------------------------------------
#include <sys/ioctl.h>
#include <fcntl.h>
#include <termio.h>
main(argc, argv)
char **argv; {
struct termio tbuf;
int fd;
char ttypath[80];
if (argc != 2 || (argv[1][0] != '-' && argv[1][0] != '+')) {
write(2, "usage: dtr [+-]tty\n", 19);
exit(1);
}
strcpy(ttypath, "/dev/");
strcat(ttypath, &argv[1][1]);
if ((fd = open(ttypath, O_RDONLY|O_NDELAY)) < 0) {
write(2, "can't open ", 11);
write(2, &argv[1][1], strlen(&argv[1][1]));
write(2, "\n", 1);
exit(2);
}
ioctl(fd, TCGETA, &tbuf);
tbuf.c_cflag &= ~CBAUD;
tbuf.c_cflag |= (argv[1][0] == '-'? B0: B300);
ioctl(fd, TCSETA, &tbuf);
close(fd);
exit(0);
}
--
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Phone: +01 216 974 9210 CIS 74106,1032 MCI MAIL BALLBERY (part-time)
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