> -----Original Message-----
> From: Jim [SMTP:jvpoll@DALLAS.NET]
> Sent: Wednesday, September 11, 2002 4:57 PM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Re: [OT]: 56k modem at 250k
>
> #1 ----
>
> Does anybody know about the compression that can be agreed
> upon during an LCP (Link Control Protocol) negotiation on
> a PPP link between two modems, compression like Van Jacobson
> Compressed TCP/IP?
>
> May I guess that this compression is done my the main CPU
> in a Winmodem - and by the on-board processor on a full
> US-Robotics DOS-capable FAX-Modem?
>
> #2 ----
>
> It has also been shown that PCI modem ping-times are like
> 100 ms longer that the same modem but in an ISA slot -
> documentation of this item upon request ...
>
> (I know some Gamers that have caught onto this little item.)
>
> RF Jim
>
The ping issue has nothing to do with the PCI slot per se, it's just that
the overwhelming majority of PCI based modems are either "softmodems" and
use the host CPU for virtualy all DSP work, or are at least "controllerless"
which puts somewhat less overhead on the CPU, but still far more than a
"proper" hardware modem.  Most (but not all) ISA based modems were purely
hardware solutions, effectively the guts of an external modem and a UART on
the same board.  USB modems are also nearly always controllerless.  The only
way to guarantee to get a decent modem (which will also work with Linux etc)
is to buy an external one that uses a proper serial port connection.

Regards

Mike

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