T And E Lines-Data Communication-Lecture Notes, Study notes of Data Communication Systems and Computer Networks

Download T And E Lines-Data Communication-Lecture Notes and more Study notes Data Communication Systems and Computer Networks in PDF only on Docsity! LECTURE #32 T Lines  T Lines for Analog Lines However they can also be used for analog transmission (Telephone ons) Analog signals are first sampled and the Time Multiplexed  T 1 Frame (Figure) o DS-1 requires 8 Kbps of overhead o To understand this overhead, lets examine format of a 24-voice channel frame o Frame used on T-1 line is usually 193 bits divided into 24 slots of 8 bits each + 1 bit for synchronization (24*8+1=193) o 24 segments are interleaved in one frame o If a T-1 carries 8000 frames, the data rate is 1.544 Mbps (193 * 8000=1.544 Mbps) which is capacity of the line o T Lines are digital lines designed for digital data o connecti o docsity.com  Fractional T Lines ( o Many subscribers the T line o For example, a small business may need only one-fourth of the capacity of a T-1 line size lie in same building, they can share a T-1 line rleaved into 4 channels E-Lines Europeans use a version of T-lines called E-lines Two are conceptually identical but capacities vary Line Rate(Mbps) Voice channels --------------------------------- 30 Fiber t h –Noise Resistance –High BW Capacity Very Expensive Telephone & Cable companies have devise FTTC to employ optical fiber while keeping the expense down Optical Fiber is the medium from the Central Office of the telephone company or from main office of a cable company to the Curb The medium from the Curb to the subscriber’s premises if the less expensive twisted pair or coaxial cable  FTTC in Telephone Network o Optical Fiber is used to connect and multiplex different voice channels o Copper twisted pair coming from individual premises is multiplexed in junction boxes and converted to optical signals. Optical signals are Figures) do not need the entire capacity of o If four business of same o DSU/CSU allow the capacity of T-1 line to be inte --------------- E-1 2.048 E-2 8.448 120 E-3 34.368 480 E-4 139.264 1920 o t e Curb (FTTC) Optical fiber has many advantages: docsity.com