kb/s is kilobits/second, i.e. 1024 bits, or binary digits of information transmitted per second. OK, we know that there are 1000 meters in a kilometer etc., unfortunately the digital world uses the term kilo for 210. Just to add a further confusion, the telecomms world tends to operate in bits, but the computer world tends to operate in bytes. A bytes is a "binary word" of 8 bits. Thus a computer will refer to its storage capacity in megabytes, whereas high speed telecommunications links are refereed to as megabit per second. The subtle distinction is that usually computing jargon refers to MB, kB etc, whereas telecommunications jargon refers to Mb/s, kb/s etc - however you only have to look at advertisments in the newsaper to see that even the computer retailers don't always realise this distinction!