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A gateway is commonly used to make an ADSL connection. Asymmetric digital subscriber line ... Distance from the telephone exchange, cable characteristics, ...
But ADSL loop extenders increase these distances by repeating the signal, allowing the local exchange carrier (LEC) to deliver DSL speeds to any distance. [9] DSL SoC. Until the late 1990s, the cost of digital signal processors for DSL was prohibitive. All types of DSL employ highly complex digital signal processing algorithms to overcome the ...
ADSL2+ extends the capability of basic ADSL by doubling the number of downstream channels. The data rates can be as high as 24 Mbit/s downstream and up to 1.4 Mbit/s upstream depending on the distance from the DSLAM to the customer's premises. ADSL2+ is capable of doubling the frequency band of typical ADSL connections from 1.1 MHz to 2.2 MHz.
ADSL repeaters are deployed by rural telephone companies trying to provide rural Internet service to farms and small towns where it is impractical to place the DSLAM closer to the subscriber. Typical distance improvements with a loop extender are shown in the diagram below, with rate in megabits per second and distance in thousands of feet. [1]
Discrete Multi-Tone (DMT), the most widely used modulation method, separates the ADSL signal into 255 carriers (bins) centred on multiples of 4.3125 kHz. DMT has 224 downstream frequency bins and up to 31 upstream bins. Bin 0 is at DC and is not used. When voice is used on the same line, then bin 7 is the lowest bin used for ADSL.
G.fast is a digital subscriber line (DSL) protocol standard for local loops shorter than 500 meters, with performance targets between 100 Mbit/s and 1 Gbit/s, depending on loop length. [1] High speeds are only achieved over very short loops.
ITU G.992.3 is an ITU (International Telecommunication Union) standard, also referred to as ADSL2 or G.dmt.bis.It optionally extends the capability of basic ADSL in data rates to 12 Mbit/s downstream and, depending on Annex version, up to 3.5 Mbit/s upstream (with a mandatory capability of ADSL2 transceivers of 8 Mbit/s downstream and 800 kbit/s upstream). [1]
Tones are spaced apart by 4.3125kHz. In the Annex A, L and M frequency standards, POTS (analog PSTN voice) occupies (what would be) tones 0-3, tones 4-7 are reserved for a ‘guard band’, and the upstream DSL transmission band uses tones 8-31 in Annex A and L, or 8-56 in Annex M. In Annex B, ISDN occupies tones 0-31, DSL upstream uses tones ...