Re: Newbie question on serial ports in Linux - please help!
On Sat, 4 Jan 1997, Nathan L. Cutler wrote: Mikael == Mikael Bendtsen [EMAIL PROTECTED] writes: Mikael And by which device should I call my modem which is Mikael connected to the second serial port? /dev/cua1 or Mikael /dev/ttyS1? Where can I find out more about this? The Linux guru community seems to be divided on this question. I had always read that the cua devnames are for _dialout_ connections, and the ttyS devices are for _dialin_ connections (or was it the other way around?)... The original reason for the bifurcation in the first place had to do with locking difficulties and getty (if I'm not mistaken) and have since been fixed. As a result, cua devices are being discouraged in favor of ttyS devices for both dial out and dial in. As a seperate data point. I still use the cua device on my dialout modem, with ppp, and have no problem. It's not that they are non-functional, it's really a conformity issue, as best I can tell. To shorten the answer: use ttyS for both dial in and dial out. Luck, Dwarf -- aka Dale Scheetz Phone: 1 (904) 656-9769 Flexible Software 11000 McCrackin Road e-mail: [EMAIL PROTECTED] Tallahassee, FL 32308 If you don't see what you want, just ask -- -- TO UNSUBSCRIBE FROM THIS MAILING LIST: e-mail the word unsubscribe to [EMAIL PROTECTED] . Trouble? e-mail to [EMAIL PROTECTED]
Re: Newbie question on serial ports in Linux - please help!
Mikael == Mikael Bendtsen [EMAIL PROTECTED] writes: Mikael And by which device should I call my modem which is Mikael connected to the second serial port? /dev/cua1 or Mikael /dev/ttyS1? Where can I find out more about this? The Linux guru community seems to be divided on this question. I had always read that the cua devnames are for _dialout_ connections, and the ttyS devices are for _dialin_ connections (or was it the other way around?)... But recently I installed mgetty+sendfax (useful if you want to receive faxes, but also need to dial-up capacity on the same line) and while browsing the docs, came upon the following tidbit: Some guys seemingly can't resist posting misinformation to the net all the time, don't believe 'em. The `/dev/cua*' devices are *not* different from the `/dev/ttyS*' devices concerning data flow or modem control lines. . . . We use `/dev/ttyS*' all the time for dial-in *and* for dial-out, and believe me, it works. . . . I'd recommend against using `/dev/modem' as a link to the real device, but if you do that, make it a *hard link* to the appropriate `/dev/ttyS*'. After reading this, I switched to an all ttyS system -- i.e. I use the ttyS device everywhere instead of the cua or /dev/modem devices, and everything works great. -- Nathan L. Cutler Linux Enthusiast http://www.cise.ufl.edu/~nlc -- TO UNSUBSCRIBE FROM THIS MAILING LIST: e-mail the word unsubscribe to [EMAIL PROTECTED] . Trouble? e-mail to [EMAIL PROTECTED]
Newbie question on serial ports in Linux - please help!
Hi all! After reinstalling Debian Linux 1.1 I can't get my computer to speak with my modem (standard USR Sportser 33.6). When running Minicom or pppd nothing happens. Because I'm really a beginner at Linux I don't know where to look. It seems that my installation lacks serial communication support. And by which device should I call my modem which is connected to the second serial port? /dev/cua1 or /dev/ttyS1? Where can I find out more about this? -- TO UNSUBSCRIBE FROM THIS MAILING LIST: e-mail the word unsubscribe to [EMAIL PROTECTED] . Trouble? e-mail to [EMAIL PROTECTED]
Re: Newbie question on serial ports in Linux - please help!
On Thu, 2 Jan 1997, Mikael Bendtsen wrote: And by which device should I call my modem which is connected to the second serial port? /dev/cua1 or /dev/ttyS1? Where can I find out more about this? Install the Linux docs (doc-lnx.deb?) and you will have the HOWTO's in /usr/doc/HOWTO - or something similar. There is a Serial-HOWTO.gz file that you'll need to gunzip and read. Ed -- TO UNSUBSCRIBE FROM THIS MAILING LIST: e-mail the word unsubscribe to [EMAIL PROTECTED] . Trouble? e-mail to [EMAIL PROTECTED]
Re: Newbie question on serial ports in Linux - please help!
On Thu, 2 Jan 1997, Mikael Bendtsen wrote: Hi all! After reinstalling Debian Linux 1.1 I can't get my computer to speak with my modem (standard USR Sportser 33.6). When running Minicom or pppd nothing happens. Because I'm really a beginner at Linux I don't know where to look. It seems that my installation lacks serial communication support. If serial support is a module, you need to remove the comment from the auto line in /etc/modules to get kerneld working in time to initialize the serial ports at boot time. This should resolve your problem. And by which device should I call my modem which is connected to the second serial port? /dev/cua1 or /dev/ttyS1? Where can I find out more about this? Cuax devices are being phased out in favor of the ttySx devices. Luck, Dwarf -- aka Dale Scheetz Phone: 1 (904) 656-9769 Flexible Software 11000 McCrackin Road e-mail: [EMAIL PROTECTED] Tallahassee, FL 32308 If you don't see what you want, just ask -- -- TO UNSUBSCRIBE FROM THIS MAILING LIST: e-mail the word unsubscribe to [EMAIL PROTECTED] . Trouble? e-mail to [EMAIL PROTECTED]
Re: Newbie question on serial ports in Linux - please help!
Mikael Bendtsen wrote: Hi all! After reinstalling Debian Linux 1.1 I can't get my computer to speak with my modem (standard USR Sportser 33.6). When running Minicom or pppd nothing happens. Because I'm really a beginner at Linux I don't know where to look. It seems that my installation lacks serial communication support. And by which device should I call my modem which is connected to the second serial port? /dev/cua1 or /dev/ttyS1? Where can I find out more about this? You should be able to get the kernel to load the serial module by either A) enabling auto-loading by putting a line with the word 'auto' in /etc/modules or by B) explicitly requesting the serial module be loaded by putting a line with the work 'serial' in /etc/modules. That should do it. As for using /dev/cua1 or /dev/ttyS1 the consensus seems to be to use /dev/ttyS1. The main reason that I can see for this is that the only way to insure proper device locking is to have all programs (getty/mgetty, pppd for instance) use the same device file. The historic reason for having more than one device is that getty's (again, historic/prehistoric getty's) used to call open() on the tty device, which had the characteristic that the open() system call wouldn't return until the modem detected a carrier (after auto-answering the phone) and hence raising the CD signal high on the cable. Of course having this restriction on the tty device made it so that you couldn't really use a modem with the device since you need to talk to the modem before a connection is established. Thus a cua device was created which had the characteristic that open() would return with requiring CD to be high. In our modern day we don't need this sort of requirement because A) more sophisticated getty's have been developed, notable mgetty and B) because this characteristic can be set for a serial line with parameters to open(). Whew. At any rate nowadays if you open the modem line and establish a connection the getty (well, some gettys) will return with an open connection after carrier is detected and will then check the locks directory to see if a device lock file exists and if one does then it will sleep and wait for its next chance or otherwise will proceed as if someone was trying to log in. Now it becomes apparent why one device (/dev/ttyS1) should be used otherwise if you use /dev/cua1 then the getty will look for a lock file with ttyS1 as the name, not find it, and proceed with its login sequence. That said, if you don't use that line for dialin (and thus don't have a getty running for the line) none of this matters, but go with the flow and use /dev/ttyS1 anyway. ;) -- Jens B. Jorgensen [EMAIL PROTECTED] -- TO UNSUBSCRIBE FROM THIS MAILING LIST: e-mail the word unsubscribe to [EMAIL PROTECTED] . Trouble? e-mail to [EMAIL PROTECTED]
