allbery@ncoast.UUCP (Brandon Allbery) (04/29/86)
Expires: Quoted from <417@ukecc.UUCP> ["Re: 3B2/300 uucp ports & Permissions"], by edward@ukecc.UUCP (Edward C. Bennett)... +--------------- | All this raises the more useful question: | | 1. Can the 3B2 control its outgoing DTR signal? +--------------- $ stty 0 > /dev/ttyxx # turn off DTR $ # turning it on is more difficult, you have to open the port without $ # DCD and ioctl() the baud rate to non-zero (see below) +--------------- | 2. Can a tty port be opened without the incoming CD signal | being high? +--------------- #include <fcntl.h> #include <termio.h> #include <sys/ioctl.h> #define TTY "/dev/ttyxx" main() { int fd; struct termio ttydat; if ((fd = open(TTY, O_RDONLY|O_NDELAY)) < 0) exit(1); ioctl(fd, TCGETA, &ttydat); ttydat.c_cflag &= ~CBAUD; ttydat.c_cflag |= Bmybaud; /* substitute your baud rate */ ioctl(fd, TCSETA, &ttydat); exit(0); } The above program uses the fact that you can open for O_NDELAY a tty despite neither DTR nor DCD being asserted; you can't read or write, but you CAN ioctl. These are tested under System III (I have a much more complex version of the above C program, run as ``dtr +tty22'' or similar, ``+'' for on, ``-'' for off), but should work under sys5 because the tty structure and code hasn't changed (modulo sxt's). If you want my ``dtr'' program, let me know. --Brandon -- decvax!cwruecmp!ncoast!allbery ncoast!allbery@Case.CSNET ncoast!tdi2!brandon (ncoast!tdi2!root for business) 6615 Center St. #A1-105, Mentor, OH 44060-4101 Phone: +01 216 974 9210 CIS 74106,1032 MCI MAIL BALLBERY (part-time) PC UNIX/UNIX PC - which do you like best? See <1129@ncoast.UUCP> in net.unix.