Data Limitations for a Transmission Line

The internet is delivered to you through your transmission line and attached modem.

Due to engineering limits, some transmission lines cannot exceed some data transmission ceilings. The slowest connection is a dial-up connection, which is limited to 56 kilobit per second on a single line, because of the analog-to-digital conversion that must take place to go over a phone line. DSL, cable, and fiber optic all sidestep this limitation by being entirely digital, but still have technical limits that impose data transmission ceilings.

DSL

DSL transmission lines are based on the normal telephone lines but use a carrier wave that "rides" on top of the normal analog voice signal. The speed ceilings of these lines are dependent on a myriad of factors, from the quality of modems and servers to the distance between you and the telephone routing depot. Most DSL transmission lines will have a ceiling between 128 kilobit and 3 megabits per second.

Cable

Cable transmission lines use the data connection on the cable wire to transmit data in addition to video. The data transmission ceiling on cable lines is 1.5 megabits per second, which is lower than the top DSL connection but is less expensive and more common in the United States.

Fiber Optic

Fiber optic transmission lines use lasers to transmit data instead of electrical pulses. The inside of the fiber optic line is mirrored so that the laser light bounces for miles without any loss of signal strength. The data limitations for a fiber optic line depend more on the computer than the line, as there are some with speeds of 1,000 megabits per second. However, most data transmission lines available as of 2011 to consumers are rated at about 100 megabits per second.

Broadband over Powerline (BPL)

Transmitting data over a power line is a new technology as of 2011, so its limits are changing rapidly. Currently BPL lines have transmission ceilings of about 3 megabits per second. However, the range is limited and most are not available outside major metropolitan areas.

References

• FCC; High Speed Internet
• New York Government: Broadbandmap: Broadband Connection