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FDDI provides a 100 Mbit/s optical standard for data transmission in local area network that can extend in length up to 200 kilometers (120 mi). [2] Although FDDI logical topology is a ring-based token network, it did not use the IEEE 802.5 Token Ring protocol as its basis; instead, its protocol was derived from the IEEE 802.4 token bus timed token protocol.
Networks on LTE bands 1, 3 (LTE-FDD) are suitable for roaming in ITU Regions 1, 3 and partially Region 2 (e.g. Costa Rica, Venezuela, Brazil and some Caribbean countries or territories. Networks on LTE band 20 (LTE-FDD) are suitable for roaming in ITU Region 1 only. Networks on LTE band 5 (LTE-FDD) are suitable for roaming in ITU Regions 2 and 3.
For example, a walkie-talkie or a DECT phone or so-called TDD 4G or 5G phones requires only a single frequency for bidirectional communication, while a cell phone in the so-called FDD mode is a full-duplex device, and generally requires two frequencies to carry the two simultaneous voice channels, one in each direction.
Frequency-division multiple access (FDMA) is a channel access method used in some multiple-access protocols. FDMA allows multiple users to send data through a single communication channel, such as a coaxial cable or microwave beam, by dividing the bandwidth of the channel into separate non-overlapping frequency sub-channels and allocating each sub-channel to a separate user.
3NF—third normal form; 386—Intel 80386 processor; 486—Intel 80486 processor; 4B5BLF—4-bit 5-bit local fiber; 4GL—fourth-generation programming language; 4NF—fourth normal form; 5GL—fifth-generation programming language; 5NF—fifth normal form; 6NF—sixth normal form; 8B10BLF—8-bit 10-bit local fiber; 802.11—wireless LAN
Most 2G cellular systems, with the notable exception of IS-95, are based on TDMA. GSM, D-AMPS, PDC, iDEN, and PHS are examples of TDMA cellular systems.. In the GSM system, the synchronization of the mobile phones is achieved by sending timing advance commands from the base station which instruct the mobile phone to transmit earlier and by how much.
The most common example of frequency-division multiplexing is radio and television broadcasting, in which multiple radio signals at different frequencies pass through the air at the same time. Another example is cable television , in which many television channels are carried simultaneously on a single cable.
Support for both FDD and TDD duplexes as well as half-duplex FDD with the same radio access technology; Support for all frequency bands currently used by IMT systems by ITU-R. Flexible bandwidth: 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz are standardized. By comparison, UMTS uses fixed size 5 MHz chunks of spectrum.