Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!apple!netcom!uport!rduc From: rduc@uport.UUCP (Richard Ducoty) Newsgroups: comp.dcom.modems Subject: Re: telebit speed Message-ID: <332@uport.UUCP> Date: 28 Aug 90 13:54:50 GMT References: <150@grumbly.UUCP> <7841@gollum.twg.com> <1990Aug27.014916.1645@theep.boston.ma.us> Organization: Microport Systems, Scotts Valley, CA Lines: 49 rk@theep.boston.ma.us (Robert A. Kukura) writes: >In article <7841@gollum.twg.com> david@twg.com (David S. Herron) writes: > In article <150@grumbly.UUCP> root@grumbly.com writes: > >I've recently started using a Telebit T2500. I'm getting transmission > >rates of about 1700 cps from me --> uunet, but only 800-1100 cps > >from uunet --> me. =======0 > Possibly ... if the phone circuit regularly had noise in only one > direction then you would see this kind of behaviour. > What's more likely is that your machines aren't "equal". That is, > uunet is more able to recieve large bursts of characters than your > system is. > This might be because of small input buffers on your system. Poor > implementation of hardware flow control (or no flow control) on your end. > Or your system might be slow. (Face it.. Sequent's simply do not lack > for CPU cycles... ;-) ...) >It could also be due to size of the files being transferred. Your >system and uunet might not be using the same batch size for news. On >my system, 50-70K batches seem to consistently achieve better transfer >rates than 20-30K batches. ================ I should have also mentioned that calling medsys (east coast I think) using YAM and Zmodem I get transfer rates medsys --> me of 1400cps I'm running SCO unix 3.2.1 (ODT) with an "Everex Magic I/O card" - the UART is an NS16550AFN . Does SCO Unix do hardware control very well at 19200 ? Is there anything that can be done to soup it up? The bigger batches would have more data/setup overhead wouldn't they. I notice that some of the 170 byte control files have transfer rates of 50 cps (and range up to 2500 cps depending on ? ) Richard Ducoty ..uunet!claris!netcom!uport!rduc ..uunet!grumbly!root -- Richard Ducoty Microport uunet!{amdahl,amdcad}!netcom!uport!rduc Scotts Valley, CA claris!netcom!uport!rduc 408 438-8649