torkell@ifi.uio.no (Torkel Lodberg) (02/20/91)
I am currently working on a new version of the NComm communication program, and would like to support split speed modems - meaning that they read input at 1200 baud, while writing at only 75 baud. As far as I can see, this is not supported by the serial.device. On the other hand, I can see that there are a few programs that offer this "facility", so how does it work? T.Lodberg
peterk@cbmger.UUCP (Peter Kittel GERMANY) (02/20/91)
In article <CMM.0.88.666995252.torkell@kvart.ifi.uio.no> torkell@ifi.uio.no (Torkel Lodberg) writes: >I am currently working on a new version of the NComm communication >program, and would like to support split speed modems - meaning that >they read input at 1200 baud, while writing at only 75 baud. > >As far as I can see, this is not supported by the serial.device. On >the other hand, I can see that there are a few programs that offer >this "facility", so how does it work? They use serial.device only for input. The one I know does the 75 Bd output by hand over one of the handshake lines. By using timers you can do this system friendly and compatible. 75 Bd is so slow that you never should run into difficulties. There also the fact contributes that this is the sending direction where you have full control about what is happening. -- Best regards, Dr. Peter Kittel // E-Mail to \\ Only my personal opinions... Commodore Frankfurt, Germany \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk
lkoop@pnet01.cts.com (Lamonte Koop) (02/20/91)
torkell@ifi.uio.no (Torkel Lodberg) writes: >I am currently working on a new version of the NComm communication Oh no...not you too...well, mine isn't really an NComm derivative anyway :-) >program, and would like to support split speed modems - meaning that >they read input at 1200 baud, while writing at only 75 baud. > >As far as I can see, this is not supported by the serial.device. On >the other hand, I can see that there are a few programs that offer >this "facility", so how does it work? Hmm...hadn't thought about this, but perhaps you could have the device open in two ways. For example, if you were running in this "split speed" mode, you could use two IOExtSer structures, and open the device twice...once for each setup, using the appropriate structure for each, and communicating with each on a seperate level. Say, Ser_Read could be opened with a 1200 baud setting, and Ser_Write could be opened with a 300 baud request, or whatever. [Or you could set the baud rates for each after opening, as long as you perform two seperate OpenDevice() calls]. However, this is purely speculation, as I haven't attempted doing such. One note: provided this method does work, you will not be able to exclusively open the serial.device with either request...(you must set SERF_SHARED in your flags)...moreoever, you will not be able to utilize hardware handshaking with the serial.device in shared mode. > >T.Lodberg LaMonte Koop Internet: lkoop@pnet01.cts.com ARPA: crash!pnet01!lkoop@nosc.mil UUCP: {hplabs!hp-sdd ucsd nosc}!crash!pnet01!lkoop "Yes, I am their leader...now tell me where they went!"
xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) (02/21/91)
A minor comment; 75 baud is an incredibly braindead standard; lots and lots of people type faster than that. A 90 wpm secretary is putting out 450 characters per minute, or 7.5 characters per second, and that is the minimum acceptable for lots of jobs. Is this worth supporting? Kent, the man from xanth. <xanthian@Zorch.SF-Bay.ORG> <xanthian@well.sf.ca.us>