On Fri, 14 Jul 2000, John Anderson wrote:

I am using a Best Data external modem that mentions a 230400 maximum throughput rate. I have a serial card that has a 16650 UART. Best Data claims that they have a driver, but only for Windows to get it to that speed. They also claim that a speed higher than 115200 doesn't give a better transfer rate. In contrast to this, I have heard many people recommend the higher transfer rates as it will help during the transfer of web pages. I also read that if the baud rate is set to 115200 than you can actually get a throughput of 230400 (with a divisor of 1). Any suggestions?

With quite-rare exceptions, a so-called 56K modem will max out at about 48Kbit (all speeds are in bits per second in this message) per second. That's going over the wire. (Lines of such low quality that the max is rather lower, are not uncommon. My ISP told me that, based on what they see going on with their other customers in the same area code and prefix I'm in, there is no real point in my upgrading from a 33.6K modem to a 56K modem, and I occasionally manage a 28K connection. And in this location I currently can't get DSL *or* cable modem - except for a DSL variant that operates at half the speed and costs twice as much.) Now, as I said, that's going over the wire. The higher numbers you see, such as 115200 and 230400, are speeds between your computer and *your* modem. This is of course absolutely pointless if the modem is not going to do some data compression; and in fact that's exactly what MNP-5 and a few other interesting modem standards are about: the modems doing on-the-fly compression and decompression. Unsurprisingly, the modems can't do anything for already-compressed stuff such as zips, jpegs, and mp3s. However, text and some other formats - such as gif, wav, and bmp - tend to be compressible. Text and bmp tend to be EXTREMELY compressible. Even with the disadvantage of doing on-the-fly compression of a data stream, 4-to-1 compression is plausible. If you're actually managing 48K on the wire, then 4-to-1 compression is nearly 200K. Even my lousy 28K connection occasionally hits 90K of throughput. -- To unsubscribe send e-mail to suse-linux-e-unsubscribe@suse.com For additional commands send e-mail to suse-linux-e-help@suse.com Also check the FAQ at http://www.suse.com/support/faq

John Anderson wrote:

I am using a Best Data external modem that mentions a 230400 maximum throughput rate. I have a serial card that has a 16650 UART. Best Data claims that they have a driver, but only for Windows to get it to that speed. They also claim that a speed higher than 115200 doesn't give a better transfer rate. In contrast to this, I have heard many people recommend the higher transfer rates as it will help during the transfer of web pages. I also read that if the baud rate is set to 115200 than you can actually get a throughput of 230400 (with a divisor of 1). Any suggestions?

------------------------ John Kerr Anderson jkanders@alpha.delta.edu SuSE GmbH 6.4 ------------------------

Unless it has changed recently, in the US the speed of a modem over normal telephone lines is limited by law. I forget the exact figure, but it is 55XXXK something. This does not apply to cable and ISDN lines, just normal telephone lines. I wouldn't listen to the claims made by a modem company anyway. Most figures they give are taken under laboratory conditions and are idea figures. Seldom would anyone get these results in a real world situation. There are too many factors that can affect the results. Nevada -- "....for the ram, by nature, is a wild and courageous animal, lonely in lonely places, whereas when tamed and made to lie down in green pastures, nothing is left but the docile, cowardly, gregarious and succulent beast. This then is the theory of government." -- Aleister Crowley -- To unsubscribe send e-mail to suse-linux-e-unsubscribe@suse.com For additional commands send e-mail to suse-linux-e-help@suse.com Also check the FAQ at http://www.suse.com/support/faq