Date: Fri, 14 Jun 96 21:46:16 +0300 From: Oleg N Panashchenko <helg@tav.kiev.ua> To: tam@cd.iidpwr.com Cc: hackers@freebsd.org Subject: Re: Digiboard Message-ID: <AAuDRmnia8@tav.kiev.ua> References: <Pine.BSF.3.91.960614092101.18723A-100000@cd.iidpwr.com>
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> I am having a very interesting situation. The baud rate on my old > DigiBoard, which utilizes 16450 chips, can be as high as 115200. But the > highest baud rate on my new DigiBoard PC/8e is only 57600. I have reports from people, who successfully use Digiboard PC/Xe at 115200. Please be more specific: what experiment resuled in this conclusion? The most correct experiment in my mind is the following: 1. Plug modem to COM1 (usual 16450) and say: $ cu -l /dev/cuaa1 -s 115200 ATZ and see OK 2. Plug modem to the first port of Digiboard and see something different $ cu -l /dev/cuaD00 -s 115200 .... Note that 115200 is not supported by low-speed MODEMS. Usually v34 (28800) modems are capable to talk with COM port at speed <=115200 v32bis (14400) modems <=57600 v22bis (2400) modems <=9600 So, look at your modem manual to verify that it can talk at 115200. > I understand > the PC/8e is "intelligent." So I assume the baud rate should be higher > too. Is that assumption correct? By the way, could you tell me what is > the differnece between PC/8e and old DigiBoard? What does "intelligent" > refer to? Main benefit of intelligent Digi is that it does not load your main CPU as much, as board with many 16450 chips. As a result, your box can handle more incoming connections simultaneously at higher speeds. To receive a byte from 16450 chip you need to service one interrupt request. Typical computer can handle about 10K serial interrups per second = 80000 bps total - on all ports (hackers, please, correct me if I'm wrong). At the other side, with intelligent Digi data is buffered in the board memory (several K bytes per channel), so they can be transferred to PC memory much more efficiently - it is no problem to serve 16 or even more high speed modems with this board. > What is the maximum baud rate on PC/8e? 115200 > Tony Tam > > +------------------------------+-----------------------------------------+ > | Tony Tam | Imperial Irrigation District | > | Imperial Irrigation District | 333 E. Barioni Blvd. | > | email: tam@cd.iidpwr.com | P.O. BOX 937 | > | tel: (619) 339 9454 | Imperial, CA 92251 | > | fax: (619) 339 9189 | U.S.A. | > +------------------------------+-----------------------------------------+ Oleg
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