Difference between T1, DSL and Satellite Internet Connection

I have often come across people who confuse T1 with DSL and I know why. It is probably because T1 is known as Digital Signal 1 (DS1). I have received curious questions such as what does satellite Internet connectivity mean. And I finally decided to resolve some of these doubts by writing about all the three technologies. Let us look at each of them.

What is a T1 Carrier?
T1, also known as the DS1 carrier, is a T-carrier signaling system that is used for the transmission of voice and data. It was developed by the Bell Labs and is popularly used in Japan and North America. The term ‘T-carrier’ is used to denote the digitally multiplexed telecommunication carrier system developed by Bell Labs. DS1 refers to the bit pattern used on the T1 line. Twenty-four 8-bit channels make up a DS1 circuit, wherein each channel is a 64 kbps carrier circuit. A T1 line can carry data at the rate of 1.544 megabits per second. It can be plugged into a telephone system to carry voice signals or be plugged to a network router to carry data. It facilitates reliable communication and performs fairly well.

What is DSL?
Wondering what DSL stands for? Well, it is short for Digital Subscriber Loop, which is a set of technologies that provide data transmission over local telephone networks. DSL has come to be known as digital subscriber line. Consumer DSL services offer speeds ranging from 256 kilobits per second to 24,000 kilobits per second. DSL that supports voice transmission works by dividing the frequencies on a telephone line into two bands. The higher-frequency band is used to carry data while the lower one is used for carrying voice signals. In a DSL setup, a DSL transceiver is plugged into the telephone line of the user. For Internet access, it performs a self-test. It then checks its connection between itself and the computer to which it is connected. Lastly, it synchronizes itself to match with the performance characteristics of the line in use. I don’t want to confuse you by adding another technology to this discussion but those interested can go through this comparative study of DSL and cable Internet connection.

Satellite Internet Connection
Satellite Internet connection is a system whereby upstream and downstream data are transmitted between computers through a satellite. A satellite Internet connection setup consists of a satellite dish antenna and a transceiver, which use the radio spectrum for data transmission. Uplink speeds are lesser than downlink speeds, which depend on the Internet traffic and server capacities. As the signals have to travel large distances, satellite communication experiences high latency periods, which means that the interval between requesting data and receiving a response is long. In general, satellite Internet access is of great use in locations where terrestrial Internet access is not available. Satellite Internet services are best for mobile use. They provide the users with an all-time and worldwide Internet connectivity.

Difference between T1, DSL and Satellite Internet
The basic difference between T1 and DSL is the price. A T1 that offers a speed of about 1.5 Mbps costs much more than a DSL line. Moreover, a T1 line directly connects to a 1.5 Mbps port while a DSL connects to a DSLAM, a multiplexer that allows telephone lines to connect to the Internet. T1 connections enable a consistent and undisturbed throughput via a dedicated port, while the performance of a DSL line is based on the amount of traffic on the DSLAM. Another important difference between the two technologies is distance. While DSL is distance-sensitive and works in a range of about 15000-18000 feet, a T1 line can be made available in remote areas and it works over a range of 20-50 miles.

How is the satellite Internet different from DSL? Firstly, the satellite Internet gives the users a permanent connectivity to the Internet, providing a two-way Internet access and a constant bandwidth. Satellite service can be accessed anytime and anywhere. This is not true in case of DSL Internet connection. As DSL works through telephone lines, it neither offers a constant speed nor a ready availability. Also it involves a huge amount of cabling, whereas satellite Internet does not require any amount of wiring.

All the three means of Internet access have their own pros and cons. They have certain comparative advantages over each other. Ultimately it is you, who has to decide which technology to go for. And now that you are equipped with some knowledge about each of the technologies, the decision will be easier!