<b>Definition 1.</b> - A high-speed digital
connection capable of transmitting data at a rate of approximately 1.5
mega bits per second. A <a href="http://www.shopfort1.net">T1
line</a> is typically used by small and medium-sized companies with
light network traffic. It is large enough to send and receive smaller
text files, graphics, sounds, and databases in a reasonable time, and
is  one of the slower speeds commonly used to connect networks to the Internet. Sometimes referred to as a leased line, a T1 is basically too large and too expensive for individual home use.

<b>Definition 2.</b> - A type of high speed Internet connection that
provides a reasonable amount of bandwidth. Many businesses lease T1 lines to connect to the Internet, but because they are expensive and offer more bandwidth than most small businesses and homes need, they are not realistic solutions for small and low-demand Internet users.

<b>Definition 3.</b> - The T1 (or T-1) carrier is the most commonly used digital line in the United States, Canada, and Japan. In these countries, it carries 24 pulse code modulation (PCM) signals using time-division multiplexing (TDM) at an overall rate of 1.544 million bits per second (Mbps). T1 lines use copper wire and span distances within and between major metropolitan areas. 

<b>Definition 4.</b>- The T-carrier system, introduced by the Bell
system in the US in the 1960's, was the first successful system that
supported digitalised voice transmission. The original transmission
rate (1.544 Mbps) in the T1 line is decreasing in use todaybecause of
its slower speeds for ISP (Internet Service Provider) connections to the Internet.