Glossary (Black Box),
Glossary (Communication News),
and a web-related
and even the
communications entry in the
Communication Speeds and Distances
Communication Speeds and Distances
- Fiber Ethernet. Fiber optics that mimic Ethernet, but much
greater distances (up to 2km).
- Ethernet running over unshielded twisted-pair at 10Mbs, effective
network diameter 250m.
- (Advanced Intelligent Network).
- (Alternative Local Transport Service).
- [IEEE 802.12 100VG-AnyLAN] 100Mbps using the new DPMA technology,
connects to Ethernet, Token Ring, and others, being developed by HP &
- A wireless carrier started in 1984 by IBM. 19,200bps (since 1993,
still 4,800bps in some areas), 256 byte packets. 800 Mhz, uses 2 watts
to transmit. Has 35,000 customers in over 400 metropolitan areas in
the US (1993) 90% of US business locations.
- (Asynchronous Transfer Mode) 45Mbps - 622Mbps (45Mbps & 155Mbps
are specified in the draft ATM standard). ATM networks are proposed to
run at over 2Gbps. Some switches up to 140Mbps are now (4/93)
available. They comprise DS3 (T3) WAN, FDDI LAN, Fiber Channel LAN,
and SONET LAN linked using SNMP. Data converted into fixed length 53
byte cells (48 byte cell + 5 byte header) facilitating high speed
switching. (AAL 3/4 (ATM Adaptive Layer) supports 44 byte cells and
AAL 5 supports 48 byte cells.)
- Literally, changes in state per second, and since this is usually
only two states (high and low voltage) it is the same as bps. If one
or two parity bits are used per 8 bit character transmission the 8 bit
byte throughput will be slower than bps/8.
- 103 Standard for 300bps modems in the United States, originally
developed at AT&T Bell Laboratories.
- Bell 212A
- Standard for 1200bps modems in the United States.
- bits per second.
- (Copper Distributed Data Interface) is FDDI running on unshielded
- (Code Division Multiple Access) Still in the trial stages
(5/1996) Developed by Motorola and Qualcom. A digital data network in
the US for use by cellular phones. This and TDMA are likely to become
the dominant digital cellular system in the US (2/1996). In Europe and
Asia it is GSM.
- (Cellular Digital Packet Data) A wireless carrier, an inernet
protocol based network, who's specs have just been finalized (1993).
19,200bps, 114 byte packets. 800 Mhz, uses 0.6 3 watts to transmit.
Operates in the 9000 cell sites. Sends digital data over idle
analog voice channels, such as CSC.
(see PCWeek 13 13, 4,3/34,34 29 Jan 1996 for CDPD distribution)
- (Custom Area Signalling Service).
- (Common Office) telephony term for switch house.
- (Circuit switched cellular) 2,400bps - 14,400bps analog system
designed for voice communication, but with cellular phone and cellular
modem gets improved data transmission.
- (Carrier-Sense Multiple Access/Collision Detection) Fast
ethernet, similar to `old' ethernet technology.
- (Digital European Cordless Telecommunications) Standard for radio
- (Direct Invaded System Access).
- (Demand Priority Access Method)
- (Distributed Queue Dual Bus) fibre optic based.
- (Digital Signal level 0). International term for 64Kbps digital
- CCITT E1 multiplexes 32 64Kbps digitized voices circuits onto a
2Mbs link, and is the European equivalent of the US T1. (The Japanese
have such a protocol similar to the US T1, but they are all different
- [IEEE 802.3] 10Mbps (14,800 64 byte packets per second theoretical
limit). MTU is 1500 bytes. (Minimum packet size is 72 bits.) Only
goes 0.5km. Runs on (originally) 1/2 inch diameter shielded cable, a
lighter coaxial (thinnet), or even shielded twisted pair cable.
Currently (1993) connects 25 million computers.
The efficiency of Ethernet is roughly a function (a), computed as five
times the length of the line in kilometers times the capacity of the
system in megabits per second, divided by the packet size in bits. When
a exceeds a certain level (Leonard Kleinrock of UCLA sets it at 0.05),
Ethernet's efficiency plummets.
See also gigabit ethernet, below.
- Fast Ethernet
- 100Mbps, effective network diameter of 250m, runs on unshielded
twisted pair cable.
- (Fibre Channel Standard) 155Mbps.
- (Fiber Distributed Data Interface) 100Mbps (170,000 64 byte
packets per second theoretical limit) using 1300nm light wavelengths.
Fiber optic, orange cable. Dual-attached counter-rotating token ring
topology. Goes 2km, with networks limited to approximately 200km
- FDDI II
- Faster FDDI. Gbps.
- (Frequency Division Multiple Access)
- fiber optic
- Fiber is much more expensive than copper but goes longer distances
more accurately because it fades much less with distance, and has a
very low error rate (1 in 1012 ), being unaffected by RFI (RF
interference). Speed of electrons in copper wire is about the same as
light in fibre (.6 speed of light in a vacuum, or 180,000 km s-1) but
light can be turned on faster than signals can be generated, and so
light signals can be packed much more closely together, resulting in
faster switching and faster network.
- The five Gigabit per second testbeds have completed their
systems: AURORA, BLANCA, CASA, NECTAR, VISTANet. The sixth is
- Gigabit Ethernet (from the 802.3z Task Force)
- 1Gbps, effective network diameter: 500m over multinode fiber, 2Km
over singlemode fiber, 25m over copper, (and 100m over Category 5
unshielded twisted pair). Due to appear in mid-1997.
- (Global System for Mobile communication) The cellular network
(900MHz range) used throughout Europe and Asia. See CDMA and TDMA.
Being used on the 1900MHz for PCS by American Personal Communications
in the Washington/Baltimore are (5/1996).
- Up to 1.6Gbps (32 bit - 800Mbps, double wide (64 bit) 1600Mbps).
(Developed at Los Alamos National Labs, MN) 10km with fibre optic
cable, but only 36m with coaxial cable.
- (Hewlett-Packard Interface Loop) An obsolete HP protocol from the
80s. A low power, low cost proprietary network running at 5Kbps with a
range of over 100m, for connecting low power, smart peripherals and
- (10/92) 7500 networks, 1 million computers, 4 million users, 100
countries. [(1991) The Internet is a federally funded computer
network, with one million users, 118,000 hosts at colleges, DARPA, NSF,
NASA, DoE, DoH&HS, &c.]
- Isochronous Ethernet
- [IEEE 802.9] ISOEnet, by National Semiconductor.
- Isochronous Ethernet.
- standards committee, formerly CCITT.
- (Local Area Network).
- Legacy LANs
- Ethernet, Token Ring, FDDI.
- LocalTalk Apple's network.
- 256Kbps, range 1000 feet.
- (Maximum Transmission Unit) Largest amount of data that can be
transported in a single internet packet.
- (Optical Carrier level 1) (STS-1) 51.84Mbps SONET.
- (Optical Carrier level 3) (STS-3 or STM-1) 155.52Mbps SONET.
- (Optical Carrier level 12) (STS-12 or STM-4) 622.08Mbps
- (Optical Carrier level 24) (STS-24 or STM-8) 1244.16Mbps
- (Optical Carrier level 48) (STS-48 or STM-16) 2488.32Mbps
- (IS-661) Falls between TDMA and CDMA
- (Personal Communication Service) There are four PCS systems (May
1996) - TDMA, CDMA, GSM, and Omnipoint. Narrow band PCS will offer
two-way paging service in 1995. Broad-band PCS will offer voice and
data communication at around 9,600bps in 1996.
- (Packet Transfer Mode) variable-sized packet technology, with
enhanced performance over ATM, originally developed by IBM.
- RAM Mobile Data
- A wireless carrier started in 1991. 8000bps (19,200bps - 1995),
512 byte packets. 900 Mhz, uses 2 watts to transmit. Uses mobitex
standard. Works with RadioMail. Has 10,000 customers in over 100
metropolitan areas in the US (1993).
- (Shielded twisted-pair Distributed Data Interface) Same as FDDI
but over shielded twisted pair.
- (Synchronous Digital Hierarchy) The SONET STS-n (or OC-n)
- (Switched Multimegabit Data Service). RBOC's version of
- (Simple Network Management Protocol).
- (Synchronous Optical Network) There are specifications for
51.84Mbps to 2488.32Mbps (See STS-n (OC-n) and STM-n).
- (Synchronous Transport Module level 1) (OC-3 or STS-3) CCITT
specification for SONET at 155.52Mbps.
- (Synchronous Transport Module level 4) (OC-12 or STS-12) CCITT
specification for SONET at 622.08Mbps.
- (Synchronous Transport Module level 8) (OC-24 or STS-24) CCITT
specification for SONET at 1244.16Mbps.
- (Synchronous Transport Module level 16) (OC-48 or STS-48) CCITT
specification for SONET at 2488.32Mbps.
- (Synchronous Transport Signal 1) (OC-1) 51.84Mbps SONET.
- (Synchronous Transport Signal 3) (OC-3 or STM-1) 155.52Mbps
- (Synchronous Transport Signal 12) (OC-12 or STM-4) 622.08Mbps
- (Synchronous Transport Signal 24) (OC-24 or STM-8) 1244.16Mbps
- (Synchronous Transport Signal 48) (OC-48 or STM-16) 2488.32Mbps
- A digital carrier facility used to transmit a DS1 formatted
digital signal at 1.544Mbps. Equivalent to 24 voice channels (DS0)
digitized at 64Kbps.
- 3.153Mbps, equivalent to 2 T1s or 48 voice channels.
- 6.312Mbps, equivalent to almost 4 T1s or 94 voice channels.
- A digital carrier facility used to transmit a DS3 formatted
digital signal at 44.746Mbps. Equivalent to 672 voice channels or 28
- 273Mbps, equivalent to 6 T3s or 4032 voice channels.
- (Thomas-Conrad Networking System) 100Mbps proprietary networking
system based on ARCnet. Runs on fiber, coax and shielded twisted
- IP datagrams have an IP header followed by a TCP segment header
followed by data.
- (Time Division Multiple Access). A digital data network in the US
for use by cellular phones. This and CDMA are likely to become the
dominant digital cellular system in the US (2/1996). In Europe and
Asia it is GSM.
- [IEEE 802.5) 4 or 16Mbps (30,000 64 byte packets per second
theoretical limit). Ring type of LAN, currently (1993) connecting 10
- V.34, 28.8Kbps standard, the last gasp of analog data
- (Wide Area Network).
- wireless technologies
- see Ardis, CSC, CDPD, RAM Mobile Data, and PCS.
Other random references:
3 3 page 58, May 1996