Messages in this thread |  | | | Date | Sat, 7 Nov 1998 09:19:29 -0500 (EST) | | From | David G Hamblen <> | | Subject | Re: Dreadful xfer rates and TCPv4 bad checksum in 2.1.1xx with PPP |
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Brian Gerst wrote: > >David G Hamblen wrote: >> >> Responding to my own post, I've got a little more info. I borrowed a >> Gateway Telepath xjack pcmcia 33.6 fax/modem, and it works fine at >>33.6K. >> Conclusion: something about my serial port (16450) and the serial >>driver >> is garbling data. The internal modem on COM2 and the Hayes modem on >>COM1 > both give lots of checksum errors and slow transfers at 14.4, while the >> pcmcia modem works well. > >If it's a 16450, that's your problem. you need a 16550(a) to reliably >handle speeds above 9600 bps. The '450 doesn't have a FIFO, so an >interrupt is generated for _every_ byte sent/received. This leads to >dropped characters, hence the checksum errors.
Yes, but the 16450 works on Win95, linux 2.0.33, and linux 2.1.xxx thru the mid 80's.
Dave
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