> -----Original Message-----
> From: David Gillett [mailto:[log in to unmask]]
> Sent: Monday, February 22, 1999 2:04 PM
> To: [log in to unmask]
> Subject: Re: [PCBUILD] US Robotics or Puretek???
>
> "WinModem" is a USR trademark.
>
> However, USR continues to make their "Sportster" and "Courier" (top
> of the line) models, and I suspect that many of the customers
> who would
> be satisified with a WinModem are wooed away by their even-cheaper
> competition. They do sell WinModems, but I wouldn't assume they
> comprise "most" of their sales....
Well alot of USR/3COM OEM sales are to companies like Dell, and they do use
WinModems exclusively.
USR isn't the only one making "WinModems" Rockwell has for years made RPI
(Rockwell Packet Interface) modems that were just the Datapump minus the
controller. PCTel is also making "WinModems." Also on a side note All PCI
Modems are "Controllerless" (Translate WinModems).
Alot of people bash so called WinModems. They had alwayz shown these
hideous examples of 40% CPU Utilization...and well that is just not the
case. PCI Winmodems might steal System RAM and CPU cycles to do what is
normally done by an Onboard Controller...however the Controller is only
responsible for Modem I/O, not for doing the PWM that is required to
actually do the Modulation and Demodulation of the DATA (that MoDem part)
plus the I/O is done over the PCI bus; The PCI Bus is some 4x MHz, 4x Bus
Width of you typical XT (Yeah 8bit still)Bus Modem, not to mention that alot
of PCI Bus Modems use Busmastering DMA to transfer data, which makes even
less of a strain on our CPU. We are only talking 53.3Kpbs in the US, not a
problem with the 133MB/sec Bandwidth we have on our PCI Bus. Also PCI is
known for it's IRQ Sharing and flawless configuration method (minus some
Compaqs with a Broken PCI BIOS).
All of these Contollerless modems aren't the same though. the Cirrus,
Lucent, TI, and Conexant (formerly Rockwell Semi) PCI ASICs are well
designed. however the PCTel Modems are inferior
crap. PCTel modems aren't just Controllerless they use the CPU to do the
PWM (Pulse Width Modulation) that is typically handled by the DSP onboard
the Modem ASIC, thus making the Argument that WinModems are inferior a
reality once again.
Thanks to PCTel we now have to clarify between a Host Controlled Modem
(Cirrus, Conexant, TI, Lucent) and a Modem which uses Host (your Pentium II
or whatevah) Signal Processing. Even with MMX; Host Signal Procesing is a
bad idea. As Signal Processing is required of your CPU even while your
connection is quiescent (ie up; but with no data actually being transfered).
for more info seek:
http://www.lucent.com/micro/K56flex/PN96053.html
http://www.cirrus.com/products/overviews/md56xx_3.html
http://www.conexant.com/products/modems/v90/hcf_soft56/default.asp?L1class_I
D=10&L2class_ID=22&L3class_ID=64&action=level_three#9
http://www.pctel.com/products/whtpap.html
¤º°`°º¤ø,¸¸,ø¤º°`°º¤ø¤º°`°º¤ø,¸¸,ø¤º°`°º¤øøº°`°º¤¤º°`°º¤ø,¸¸,ø
Dave Hendricks: Linux-Junkie; MCP; Systems Integrator.
[log in to unmask]
>
Do you want to signoff PCBUILD or just change to
Digest mode - visit our web site:
http://nospin.com/pc/pcbuild.html
|
