Xref: utzoo comp.sys.ibm.pc.misc:10557 comp.dcom.modems:10476 Path: utzoo!utgpu!news-server.csri.toronto.edu!torsqnt!lethe!tvcent!comspec!censor!isgtec!ted From: ted@isgtec.uucp (Ted Richards) Newsgroups: comp.sys.ibm.pc.misc,comp.dcom.modems Subject: Re: 4.77MHz PC sufficient for 19200 bps modem? Keywords: modem, pc Message-ID: <1155@isgtec.UUCP> Date: 19 Jun 91 12:57:18 GMT References: <1991Jun18.201125.6198@cs.cmu.edu> Sender: news@isgtec.UUCP Reply-To: ted@isgtec.UUCP (Ted Richards) Organization: ISG Technologies Inc. Mississauga Ont. Canada Lines: 40 In article <1991Jun18.201125.6198@cs.cmu.edu> jch+@cs.cmu.edu (Jonathan Hardwick) writes: > Question for the net: > > A housemate has an original Big Blue IBM PC, running at the blazing > speed of 4.77MHz. We want to use this as a dumb terminal to access > our university workstations. The university offers 2400 bps service > with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV > modems. We'd really like the extra speed if possible. Is the PC > going to be able to keep up with 19200 bps? How about 9600 bps? I have some bad news for you. I have one of these geriatric beasts, too, and it doesn't even come close to keeping up at 9600 baud. The problem is in the screen updates, not the comms port, which manages file transfers at almost full speed (~ 860-920 cps). The speed varies depending on the comms programm. I have tried Procomm, Telix and two varieties of MS_kermit. Telix is really awful (unfortunate, because I like the programm a lot). Even with Telix doing its own screen updates (the fastest mode), it fills the screen at perhaps 300 cps when scrolling, somewhat better when clearing the screen first. The latest Kermit is not much better. Procomm was, I think, a little faster, but I tried it a year ago, so I don't remember exactly. The best performance, perhaps 500-600 cps, comes from a very old copy of Kermit, dated 1982 or 1983 that I found lying around on an old diskette. Perhaps someone else has found another comms program that can keep up? By the way, I am using a Telbit T1000 on my end, talking to a T2500 (at 9600 baud) at work. > Oh, and if the PC *can't* keep up, what sort of motherboard upgrade > would we need? 10 MHz 8086? 80286? Can't help you here, since I haven't done anything about it (I'm saving up for a 386-25, myself). -- Ted Richards ...uunet!utai!lsuc!isgtec!ted ted@isgtec.UUCP ISG Technologies Inc. 3030 Orlando Dr. Mississauga Ont. Canada L4V 1S8