news@norlin.se (news) (06/10/91)
I know this subject has been up before, but I still don't know the answer. Probably most answers has been e-mailed to the poster directly. How can I use RTS/CTS-flow under SCO Xenix 2.3.3? I think I know that the standard serial device drivers don't support hardware flow control, so...where can I get some that really does? I am very greatful for all help I can get... * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Stefan Norlin, Forma Data AB * * * Box 202, 126 02 HAGERSTEN * Nothing compares to a good ..ck! * * SWEDEN * Ooops! Should be "hack", of course...:-) * * stefan@norlin.se * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
curt@cynic.wimsey.bc.ca (Curt Sampson) (06/11/91)
In article <108@norlin.se> news@norlin.se (news) writes: > How can I use RTS/CTS-flow under SCO Xenix 2.3.3? > > I think I know that the standard serial device drivers don't support > hardware flow control, so...where can I get some that really does? The sio driver in SCO Xenix 2.3.2 does support RTS/CTS flow control, though in a different way than you might be used to. (This is probably true of all versions of SCO Xenix.) The RTS/CTS control flow, when turned on, is implemented as follows: When the computer has data to send it will raise RTS. The computer will then wait for the modem to raise CTS to indicate that the modem is ready to receive data. The computer will send data as long as CTS is asserted, until it runs out of data, at which point it will lower RTS until it has more data to send. Obviously, this is only unidirectional flow control, with the modem controlling the computer. The CTS protocol can be turned on by setting CTSFLOW, either by an "stty ctsflow" or by adding CTSFLOW to the entry for that terminal type in the /etc/gettydefs file. (Make sure you add it to the final-flags section as well as the initial-flags section.) RTS can be enabled in the same way using RTSFLOW. This will do the job for most modems. If you have a slower system, though, you may need to implement bidirectional flow control. CTS is used in the same way, but the computer asserts RTS when it is ready to receive data. The modem will not send when RTS is not asserted. The standard SCO sio driver does not support this mode, unfortunately. Fortunately, though, there is a serial driver known as FAS (Final Async Solution) that supports this bidirectional RTS/CTS flow control as well as the more traditional SCO sio method of flow control. As an added bonus, it will also utilise the FIFO buffers in your NS16550A UARTs, if you have them. (If you have a high-speed modem and you don't have it on an intelligent serial board, you should have one of these.) FAS does seem to have a problem with DTR. The details of that are available in a post I made here recently. Hopefully that will be resolved soon. To find out where to get FAS via FTP, use archie. Just telnet quiche.cs.mcgill.edu and login as "archie". cjs -- | "This sound system comes to you with fuel injection. Curt Sampson | Toes tapping, the unthinking masses dance to a new curt@cynic.uucp | tune. . . . Undress yourself to this bastard. Suck curt@cynic.wimsey.bc.ca | on this plan of noise, bimbo!" --Gary Clail