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RE: [TCLUG:3624] A new subscriber...



On 23 Jan, Barnholtz, Brian wrote:
> I use Xisp and it works great for my connection.  I do have a general
> question though.  I have my modem set for 115200 and it claims to
> connect at that speed, however, my download is anywhere between 3k/sec
> and 9k/sec.  I thought it was impossible to transmit at speeds over 56k
> due to limitations within the phone lines??? Does anyone know what the
> formula for converting k/sec into an actual baud speed?
k/sec is kilobytes per second, so 9k/sec is 9,000 bytes per second. 
 Take that times 8 and you have bits per second.  This is bps and what
 people generally call baud.  So if you have a 56k modem you should get
 56,000 bits per second, unfortunatly the phone company limits you to
 somewhere around 46,000 bits per second because of multiplexing.  

So how are you getting 9k/sec which is 72,000 bits per second?  Well
it's all in the compression.  People use compression over ppp many
times so you can get throughput that's well over your actual linespeed.
 This compression is different than the hardware compression that the
 modem actually uses to get over the actual 9600 bits per second limit.
-- 
Jon Schewe 
http://tcfreenet.org/~schewe
schewe@tcfreenet.org