What is DSL?
Digital Subscriber Line (DSL) is technology that provides high speed internet connection. DSL uses existing copper pair phone line wiring in conjunction with special hardware on the switch and user ends of the line. This special hardware allows for a continuous digital connection over the phone lines.
DSL Internet allow users to receive data at 1.5 Mbps and send data at approximately 256 Kbps, though actual speed is determined by the proximity to the providers central office. DSL service is always on – users don't need to dial a connection to gain access to the Internet – and some services even allow users to use the same line for voice and data traffic.
Types of DSL?
ADSL (Asymmetric Digital Subscriber Line) employs two different transmission speeds, with the downstream speed (from the provider to the user) usually being much higher than the upstream speed (from the user to the corporate host). ADSL can achieve downstream data rates up to 8 Mbps and upstream rates to 1 Mbps.
IDSL (ISDN Digital Subscriber Line) is a form of DSL that uses ISDN provisioning and testing, and can coexist with current analog and ISDN services. IDSL is usually limited to 144 Kbps upstream and downstream, but can sometimes provide further reach than other DSL solutions because it does not have the same distance limitations.
VDSL (Very High Speed Digital Subscriber Line) promises even higher speeds than ADSL, although over much shorter distances. Standardization on speeds and technological specifications are currently in progress.
RADSL (Rate Adaptive Digital Subscriber Line) adjusts the data transmission rate to match the quality of the phone line. RADSL users get the very best performance their telephone line is conditioned to provide, providing transmission rates of up to 7 Mbps downstream and 1 Mbps upstream.
HDSL/SDSL (High Data Rate Digital Subscriber Line/Symmetric Digital Subscriber Line) utilize two standard phone lines for 1.5 Mbps transmission speeds and offer the capability to combine three phone lines for 2.0 Mbps speeds. HDSL and SDSL are intended as lower cost replacements for dedicated and fractional T-1 lines 2 .
Advantages of DSL
DSL is :
- DSL is more cost-effective because it eliminates the need for extensive and expensive infrastructure upgrades.
- DSL service requires no new phone lines and little new equipment.
- DSL is always on service that does not require unreliable dial up connections
Disadvantages of DSL
The greatest disadvantage is availability. Although DSL service is widely available in most metropolitan areas, is often not available in non-metropolitan or rural areas because the distance sensitivity limitation.
DSL Broadband Internet Providers
AT&T DSL Broadband Internet for $14.95 a month
- Up to 3.0 Mbps download speed
- Starting from only $14.95/mo
- 50% off wireless gateway ($50 value) or modem ($38 value) after rebate for new Internet customers with new or existing AT&T Wireless or AT&T | DIRECTV. Online redemption required.
- Wi-Fi access for Internet on the go
- AT&T Internet Security Suite - powered by McAfeeŽ ($5/mo value)
Verizon DSL Broadband Internet for $14.99 a month
- Up to 15 Mbps download speed
- Starting from only $14.99/mo
- Best Price Online: Includes $5 OFF per month for 1 year
- A wireless router (online orders only) at no extra cost -- a $34.99 value
Qwest (now CenturyLink) DSL Broadband Internet for $14.95 a month
- $14.95 per month for 12 months when you bundle
- Up to 40 Mbps download speed