DSL Paired Numbers Explanation Paired numbers are commonly used to describe a DSL connection speed. Both numbers represent the speed of transmission. The first number represents the transmission speed of data coming to your computer - coming "down", or the "download" speed. The second number represents the transmission speed of data going from your computer - going up, or the upload speed. The transmission speed is measured by the amount of data - a bit - transmitted in a given time - one second. Computer data - meaning anything that is used to store or display data in language that your computer uses - is comprised of bits. Bits make up one dot of an image. Many image dots make up the picture you see on your screen. So, for example, 768k would translate to 768 kilobits - which is "thousands of bits" - per seconds. This number, in a longer form, is written - 768kbit/s, then shortened to 768kbs, and then shortened to just 768k. Thus - 768k/128k means that this DSL line speed is capable of downloading data at speeds of up to 768,000 bits of data per second, and capable of uploading data at speeds of up to 128,000 bits of data per second. When the numbers increase past 999,999, past "thousands", and move into "millions," the "K' which represented "kilo" - thousand - switches to "m", which is short for "mega", or "million". Thus, 3m is short for 3,000,000, or when used as a DSL speed descriptor means 3,000,000 bits (or megabits) of data per second. The reason why the first number is usually higher than the second is because most "traffic" is downloading, or incoming, so most of the "width" of the line is reserved for downloading.