What is The speed of...? - Definition from WhatIs.com
Part of the Smart grid glossary:

This table shows the stated data rates for the most important end-user and backbone transmission technologies.

Technology Speed Physical Medium Application
GSMmobile telephone service 9.6 to 14.4 Kbps RF in space (wireless) Mobile telephone for business and personal use
High-Speed Circuit-Switched Data service (HSCSD) Up to 56 Kbps RF in space (wireless) Mobile telephone for business and personal use
Regular telephone service (POTS) Up to 56 Kbps twisted pair Home and small business access
Dedicated 56Kbps on frame relay 56 Kbps Various Business e-mail with fairly large file attachments
DS0 64 Kbps All The base signal on a channel in the set of Digital Signal levels
General Packet Radio System (GPRS) 56 to 114 Kbps RF in space (wireless) Mobile telephone for business and personal use
ISDN BRI: 64 Kbps to 128 Kbps
PRI: 23 (T-1) or 30 (E1) assignable 64-Kbps channels plus control channel; up to 1.544 Mbps (T-1) or 2.048 (E1)
BRI: Twisted-pair
PRI: T-1 or E1 line
BRI: Faster home and small business access
PRI: Medium and large enterprise access
IDSL 128 Kbps Twisted-pair Faster home and small business access
AppleTalk 230.4 Kbps Twisted pair Local area network for Apple devices; several networks can be bridged; non-Apple devices can also be connected
Enhanced Data GSM Environment (EDGE) 384 Kbps RF in space (wireless) Mobile telephone for business and personal use
satellite 400 Kbps (DirecPC and others) RF in space (wireless) Faster home and small enterprise access
frame relay 56 Kbps to 1.544 Mbps Twisted-pair or coaxial cable Large company backbone for LANs to ISP
ISP to Internet infrastructure
DS1/T-1 1.544 Mbps Twisted-pair, coaxial cable, or optical fiber Large company to ISP
ISP to Internet infrastructure
Universal Mobile Telecommunications Service (UMTS) Up to 2 Mbps RF in space (wireless) Mobile telephone for business and personal use (available in 2002 or later)
E-carrier 2.048 Mbps Twisted-pair, coaxial cable, or optical fiber 32-channel European equivalent of T-1
T-1C (DS1C) 3.152 Mbps Twisted-pair, coaxial cable, or optical fiber Large company to ISP
ISP to Internet infrastructure
IBM Token Ring/802.5 4 Mbps (also 16 Mbps) Twisted-pair, coaxial cable, or optical fiber Second most commonly-used local area network after Ethernet
DS2/T-2 6.312 Mbps Twisted-pair, coaxial cable, or optical fiber Large company to ISP
ISP to Internet infrastructure
Digital Subscriber Line (DSL) 512 Kbps to 8 Mbps Twisted-pair (used as a digital, broadband medium) Home, small business, and enterprise access using existing copper lines
E-2 8.448 Mbps Twisted-pair, coaxial cable, or optical fiber Carries four multiplexed E-1 signals
cable modem 512 Kbps to 52 Mbps
(see "Key and explanation" below)
Coaxial cable (usually uses Ethernet); in some systems, telephone used for upstream requests Home, business, school access
Ethernet 10 Mbps 10BASE-T (twisted-pair); 10BASE-2 or -5 (coaxial cable); 10BASE-F (optical fiber) Most popular business local area network (LAN)
IBM Token Ring/802.5 16 Mbps (also 4 Mbps) Twisted-pair, coaxial cable, or optical fiber Second most commonly-used local area network after Ethernet
E-3 34.368 Mbps Twisted-pair or optical fiber Carries 16 E-l signals
DS3/T-3 44.736 Mbps Coaxial cable ISP to Internet infrastructure
Smaller links within Internet infrastructure
OC-1 51.84 Mbps Optical fiber ISP to Internet infrastructure
Smaller links within Internet infrastructure
High-Speed Serial Interface (HSSI) Up to 53 Mbps HSSI cable Between router hardware and WAN lines
Short-range (50 feet) interconnection between slower LAN devices and faster WAN lines
Fast Ethernet 100 Mbps 100BASE-T (twisted pair); 100BASE-T (twisted pair); 100BASE-T (optical fiber) Workstations with 10 Mbps Ethernet cards can plug into a Fast Ethernet LAN
Fiber Distributed-Data Interface (FDDI) 100 Mbps Optical fiber Large, wide-range LAN usually in a large company or a larger ISP
T-3D (DS3D) 135 Mbps Optical fiber ISP to Internet infrastructure
Smaller links within Internet infrastructure
E-4 139.264 Mbps Optical fiber Carries 4 E3 channels
Up to 1,920 simultaneous voice conversations
OC-3/SDH 155.52 Mbps Optical fiber Large company backbone
Internet backbone
E-5 565.148 Mbps Optical fiber Carries 4 E4 channels
Up to 7,680 simultaneous voice conversations
OC-12/STM-4 622.08 Mbps Optical fiber Internet backbone
Gigabit Ethernet 1 Gbps Optical fiber (and "copper" up to 100 meters) Workstations/networks with 10/100 Mbps Ethernet plug into Gigabit Ethernet switches
OC-24 1.244 Gbps Optical fiber Internet backbone
SciNet 2.325 Gbps (15 OC-3 lines) Optical fiber Part of the vBNS backbone
OC-48/STM-16 2.488 Gbps Optical fiber Internet backbone
OC-192/STM-64 10 Gbps Optical fiber Backbone
OC-256 13.271 Gbps Optical fiber Backbone

Key and Explanation

We use the U.S. English "Kbps" as the abbreviation for "thousands of bits per second." In international English outside the U.S., the equivalent usage is "kbits s-1" or "kbits/s".

Engineers use data rate rather than speed, but speed (as in "Why isn't my Web page getting here faster?") seems more meaningful for the less technically inclined. Many of us tend to think that the number of bits getting somewhere over a period of time is their speed of travel.

Relative to data transmission, a related term, bandwidth or "capacity," means how wide the pipe is and how quickly the bits can be sent down the channels in the pipe. (The analogy of multiple lanes on a superhighway with cars containing speed governors may help. One reason why digital traffic flows faster than voice traffic on the same copper line is because digital has managed to convert a one-lane or narrowband highway into a many-lane or broadband highway.)

These "speeds" are aggregate speeds. That is, the data on the multiple signal channels within the carrier is usually allocated by channel for different uses or among different users.

Key: "T" = T-carrier system in U.S., Canada, and Japan...."DS"= digital signal (that travels on the T-carrier or E-carrier)..."E" = Equivalent of "T" that uses all 8 bits per channel; used in countries other than U.S. Canada, and Japan...."OC" = optical carrier (Synchronous Optical Network)...."STM" = Synchronous Transport Modules (see Synchronous Digital Hierarchy)

Only the most common technologies are shown. "Physical medium" is stated generally and doesn't specify the classes or numbers of pairs of twisted pair or whether optical fiber is single-mode or multimode. The effective distance of a technology is not shown. There are published standards for many of these technologies. Some of these are indicated on pages linked to from the table.

Cable modem note:The upper limit of 52 Mbps on a cable is to an ISP, not currently to an individual PC. Most of today's PCs are limited to an internal design that can accommodate no more than 10 Mbps (although the PCI bus itself carries data at a faster speed). The 52 Mbps cable channel is subdivided among individual users. Obviously, the faster the channel, the fewer channels an ISP will require and the lower the cost to support an individual user.

This was last updated in March 2010
Contributor(s): Carol Cartier, Tom Payne, and Bill Turner
Posted by: Margaret Rouse

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