🚀 go-pugleaf

Peter Oakes wrote in message <35D1E9B9.42F90387@oakes.force9.net>...
>Dear Groups
>
>I have a Compaq Presario 56K-DFi modem (inbuilt into CPU), which is set
>to run at 115200 baud (ie the highest possible speed).  The highest
>speed my diagnostic test (through the Modem icon via Control Panel on
>Windows 95) also says 115K.
>
>My problem is that I have never seen the modem run at anymore than
>33.6K.
>

Hi,

This is often a subject of confusion. There are two ways to measure a modems
transfer speed:

a) Line speed (transfer rate over telephone line)

b) Port speed (transfer rate from modem to com port)

56K or 33.6K refer to the LINE speed while  115200bps is the highest
transfer rate from modem to com port. This is achievable through data
compression  i.e-  the line speed is 28.8K (28800bps) and port speed is
115200bps so the modem can use its compression algorithm to 'trim'
redunduncy in the data and can then transmit data to the com port at
115200bps.

But compression is actualy useless on the internet since most data such as
graphics is already compressed - so by enabling modem compression you can
actualy slow down transfer rates.
Also the higher to port speed the more work your CPU must do (most hardware
can't cope with more than 38400 without getting hardware overruns).

To optimise speeds - set modem speed to 57600 and disable modem compression.

If your modem is 56K you should be getting  40000bps to 50000bps on your
phone line - 33.6K might be a limitation of your ISP or in a rare case your
phone line.


Regards,

N Gilmore

A1 Computer Technology        041-822-1705