dds@spsd.uu.net (Dennis D. Sherod) (08/10/89)
Our shop is expecting some 3COM CS-210 termservers shortly and I have a question on their use for output devices. Of course its obvious the operation of termservers for directly connected terminals and dial-in modems and the like. It seems likely that they will be just as useful for printers and dial-out modems, but it doesn't seem so obvious how this can be accomplished using the pseudo-tty's. Am I missing something? How would one associate a ttyp?? with a particular port on a specific termserver? The purchase of the CS210's was not predicated on the strict use for output only devices, but it would be nice to be able to completely eliminate the host based async. -- Dennis Sherod, Data General Corporation UUCP: ..!uunet!spsd!dds 1224-B Village Way, Santa Ana, CA 92705 ARPA: sherod_d@sdsa01.CEO.DG.COM FAX: +1 714 835 6995 VOICE: +1 714 835 3583
dpz@convex.com (David Paul Zimmerman) (08/13/89)
We've got some printers connected through cisco terminal servers, and they work pretty much OK. The setup is: lpd -> ttypN==ptypN -> "lp_pty" -> cisco port X==printer where -> is a tenuous path, and == is a fairly reliable hard path. The sequence of events: - lpd talks to the tty side of the tty-pty pair - a program "lp_pty" reads from the pty side of the tty-pty pair - you can open a raw TCP connection to a particular port on cisco term servers, and have the data come out on any particular serial line. At startup, lp_pty opens up a connection to the cisco term server on port 4000 + the decimal number of the serial line. - lp_pty writes the data over the TCP connection - the cisco term server reads the data and stuffs it down the requested serial line - the printer gets the data and does whatever it is supposed to Details to get this going include renaming a tty=pty pair to something that telnetd and rlogind can't find (like printername-ttysf, printername-ptysf). lpd talks at the tty side. You then run "lp_pty" with arguments to tell it what pty to read from, what host to open the TCP connection to, and what port to open it at. I mentioned a tenuous path vs a hard path above because once in a while I have to go through and kill/restart everything, because something along the way just stops. I think it is lp_pty, so I have to work on it a bit. Of course, acknowledgements: L. Ron Natalie @ Rutgers University took 'telnet' and munged it around to become 'lp_pty'. I took it :-) David David Paul Zimmerman dpz@convex.com CONVEX Computer Corp convex!dpz