I am at an 8-way Tap . Trying to explain to you how the cable math is done. An example is if you had 15 dB at the point of entry before the 8 way. when you insert into the tap. It loses 11db. which is 15db-11db=4db.

 This is based off the Flukes Network Chart. The wiring has changed through out the years. At one time is was Cat 3.Then as time moved on they went to better cable to handle different bandwidth and to move on into the future. The Mbit/s is really Million bits per second. megabit per second (symbol Mbit/s or Mb/s, often abbreviated "Mbps") is a unit of data transfer rate equal to:  1,000 kilobits per second 1,000,000 bits per second 125,000 bytes per second 125 kilobytes per second