🚀 go-pugleaf

In <1992Aug14.151938.10653@nntp.hut.fi>, Tapio Sand writes:

>In article <q2aDPB1w164w@buscard.fidonet.org> sharky@buscard.fidonet.org (Gary
>>Anyone know why I would modem problems with windows and
>>not in DOS. I have 2 com ports and 1 internal modem at
>>com 3. The mouse is working fine as com 2 in windows
>>but I'm having flacky probs with and windows application
>>that uses a modem. Hangs system, with faults, download
>>problems. If I use the internal modem with Procomm
>>under DOS 5.0 only, everthing works fine. Do I have some

>Ah, the classic question every windows user with a fast (>2400)
>modem asks, sooner or later. The problem is that when a character
>comes in the serial port, it signals with an IRQ that the computer
>should copy the received character into memory. This has to happen
>immediately because the UART (8250 or 16450) has room for one character
>only. With windows running, there is so much activity going on that
>the CPU can't serve the serial port fast enough. This of course
>results in losing incoming charaters.

>Solution: replace your serial port UART with a 16550. This has a 16 byte
>buffer, so that the serial port can hold 16 characters before starting
>to lose data. This has solved all my friend's problems similar to yours.

>How to find out what UART you have? There must be several programs
>that can report this. The one I know of is Port Finder v2.7
>You can get it via FTP from SIMTEL20 from msdos' sysutl directory
>named  pf270.zip.

Upgrade the serial port? Even for an *internal* modem on COM3?  I was under the
impression that the UART on the serial ports were only important to external
modems running from COM1 (or COM2 if there are 2 serial ports).  When I
inquired about my upcoming upgrade to a 9600 or 14.4k *internal* modem, I was
told that an internal modem would use a 16550 on *its own card*.  Is this the
case?  Am I understanding this correctly?  Am I misinterpreting something??

I was under the impression that internal modems don't use the serial port...


Tim Irvin   j056600@lmsc5.is.lmsc.lockheed.com