Wired Media Wired transmission lines are physical systems that are used to transmit certain physical quantities. They consist of a collection of a set of conductors made up of good conductors of electricity, like copper and aluminum, and a wire. Some transmission lines used are t-1, t-3, OC lines, DSL, dial-up, and cable lines.
A T-1 line is a copper or fiber optic telephone line that can carry more data than traditional dial-up lines. These lines were originally made with twisted copper. T-1 lines are still being made, but the standard is slowly being upgraded to fiber optic lines. T-1 lines can transmit 1.544 Mbps. They connect geographically separate offices through a private voice and/or data connection. It is very useful for small businesses and commercial buildings with more than 8 lines. Getting a T-1 line is costly (around $1,500 a month), however it could save money for companies who have many phone lines.
T-3 lines are a collection of about 28 T-1 lines that can transmit data at 44.736 Mbps. Obviously they are faster than T-1 lines, because they have a collection of 28 T-1 lines. They are used for longer distances than T-1 as well. Similar to T-1 lines, they are used to connect geographically separate offices through a private voice and/or data connection. They cost upwards of $3,000 a month to operate so not all small businesses can afford to have a T-3 line.
Optical Carrier lines (OC lines), are a part of the Synchronous Optical Network (SONET). OC-1 is the base rate of Optical Carrier lines. This rate is 51.84 Mbps. These speeds go up to 40 Gbps with OC-768 levels. The integer behind the OC is the multiple of OC-1 rates (51.8 x n for OC-n).
OC 768 consists of a SONET ring to maintain its reliability during high-speed transmissions. It is so much more efficient than a single T-1 line. In fact, It is capable of transmitting 516,096 voice channels at the same time. It takes 21,504 T-1 lines to even have that many channels. Usually, Communication providers are the consumers of OC lines because of them having to be able to provide service to others. Most businesses cannot afford this expensive transmission lines.
Digital Subscriber Line (DSL) is a technology for bringing high-bandwidth information to homes and small businesses over ordinary telephone lines. There are 3 different variations of DSL. HDSL (High bit-rate DSL) is used mainly in corporate companies or between telephone companies and customers. Unlike ADSL, HDSL is symmetrical. This means that the upstream and downstream speeds are equivalent, so sending email and receiving email all flows at the same time. Which explains why corporate sites are the main users. Upstream and downstream rates reach up to rates of 1.544 Mbps on a single wire.
Another breed of DSL is ADSL (Asymmetric DSL). ADSL is the form of DSL that most homes and small businesses use. It is called Asymmetric because most of its duplex bandwidth is devoted to the downstream direction, sending data to the user. This is because most people downstream data more than they upload it to websites and other users. This helps us get what we want from our Internet faster than we would if it was asymmetric like HDSL. Downstream speeds reach up to 6.1 Mbps while upload speeds reach 640 kbps.
RADSL (Rate-Adaptive DSL) is a type of ADSL technology developed by Westell. It uses software to determine the rate at which signals can be transmitted for a given customers phone line. The better the phone line, the higher rate you will receive. Their system delivers minimum downstream at 640 kbps and their maximum is 2.2 Mbps and minimum upstream from 272 kbps up to the maximum of 1.088 Mbps all over an existing line. DSL may be not as effective as cable depending on where you are located to your provider. A DSL user must be no more than 18,000 feet away from the phone office, and the farther the user is from the phone office, the lower the bandwidth and rate of data transfer. Technical difficulties with the home's phone lines can result in lowered bandwidth, and interruptions of Internet service.

Dial-up uses the facilities of public switched telephone networks (PSTN) to establish a dialed connection to an Internet service provider (ISP) via telephone lines. Dial-up is one of the cheapest communication connections there is. Rural and remote areas still use dial-up because they it is too expensive for Internet providers to get other services out to them. The upside is that it is so affordable and easy to obtain. All that is needed to start a dial-up connection is a telephone line. However, the downside of dial-up is the extremely slow transmission rate compared to other lines and an increasing amount of Internet content such as streaming media will not work at dial-up speeds. Even at speeds up to 320 kbps with compression hardware assistance, it is still less than half the speed of cable and DSL.
The advantages of Dial-up connection are that they are cheap and secure. They are also offered in just about everywhere. Weaknesses are that you must have a phone line, and the speeds are very slow
A Cable modem is similar to an ADSL system, but instead of coming from a telephone provider through telephone lines, it comes from a cable provider through your cable TV line. Cable lines can receive up to 1.5 Mbps, which is not as fast as DSL, but you would not need to have a telephone line to receive the cable transmission. The actual bandwidth for Internet service over cable TV line is up to 27 Mbps downstream with 2.5 upstream, however, the local provider is probably not going to be connected to the Internet with lines faster than a T-1 system. So it is said that the more likely rate that will be received from a cable line is around 1.5 Mbps.