pss610@unhd.unh.edu (Paul S Secinaro) (04/16/91)
I have been trying to set up Columbia C-Kermit for use under AT&T SVR3.2.1 with one major problem. When I do a 'set line /dev/tty01' command, the system hangs completely and I have to reboot. I think I know what may be causing the problem: The device I'm connected to does not implement any control signals except the transmit and recieve lines (TX and RX in RS-232 jargon). I believe the hang up may be caused by the lack of a carrier detect signal being asserted by the remote device. Is there any way to set up a serial port so that it ignores carrier detect and other control signals? The SysAdmin Guide as well as the FAQ for this newsgroup mention something about 'modem control' ports, but I'm not sure how to set them up or if they'll solve the problem. Oh, one other thing: does anyone know where I can get a hold of the FAS driver that's mentioned in the FAQ? (FTP preferred). Thanks. -- Paul S. Secinaro University of New Hampsire pss610@unhd.unh.edu p_secinaro@unhh.unh.edu
les@chinet.chi.il.us (Leslie Mikesell) (04/18/91)
In article <1991Apr16.131028.10095@unhd.unh.edu> pss610@unhd.unh.edu (Paul S Secinaro) writes: >I have been trying to set up Columbia C-Kermit for use under AT&T SVR3.2.1 >with one major problem. When I do a 'set line /dev/tty01' command, the >system hangs completely and I have to reboot. I think I know what may be >causing the problem: The device I'm connected to does not implement any >control signals except the transmit and recieve lines (TX and RX in RS-232 >jargon). I believe the hang up may be caused by the lack of a carrier detect >signal being asserted by the remote device. >Is there any way to set up a serial port so that it ignores carrier detect >and other control signals? The SysAdmin Guide as well as the FAQ for this >newsgroup mention something about 'modem control' ports, but I'm not sure >how to set them up or if they'll solve the problem. The simple way to deal with this is to loop back your DTR lead to your DCD. Opening a tty device will always assert DTR and thus supply the needed DCD for the open to complete. Remember - hardware is easy... The software solution involves going into every program and setting O_NDELAY in the open flags, then using ioctl() to turn on CLOCAL in the termio struct, then fcntl() to clear the O_NDELAY flag. I really wonder about the guys who dreamed this stuff up! Oh well - kermit already has most of the code in place and it looks like someone intended for the command "set modem unknown" to let the script functions work like the built-in dialers, but it still wants to clear CLOCAL before letting you connect. As a quick hack, you can just compile a version that never clears the CLOCAL bit. Les Mikesell les@chinet.chi.il.us