What is VDSL?
VDSL stands for Very high bit rate Digital Subscriber Line. In layman’s terms that translates to a broadband link over a telephone line at incredibly fast speeds. VDSL is part of the family of Digital Subscriber Line technologies which operate over normal telephone wiring. The main types are shown in table 1 below. Normal ADSL is used by the majority of telephone broadband subscribers. It runs at speeds from 512 Kilobits per second (Kbps) up to 2 Megabits per second (Mbps). There are higher speed variants in the DSL family such as SHDSL which can run at up to 8 Mbps but only over shorter distances and through good quality wiring. VDSL offers up to 15 Mbps over normal in-building telephone wiring at a distance of 1 kilometer and 5 Mbps at distances up to 1.5 kilometers.
As telephone companies try to extend their optical fiber backbone networks closer to the customer it becomes prohibitively expensive to engineer a dedicated optical fiber cable for the last few hundred meters into each customer location. New communications infrastructure costs increase as they are provided closer and closer to the customer, since the resources become less shared. The last few hundred meters are the most expensive, since they will often be dedicated to a single customer. Economic reasons therefore dictate the consideration of a strategy of fiber-to-the-neighborhood (FTTN) or fiber-to-the-curb (FTTC) or for larger buildings fiber-to-the-basement (FTTB), combined with the re-use of the existing copper cable for the last few hundred yards. In these network architectures an optical fiber cable would be installed to new remote stationed equipment. The remote equipment will tap onto the existing copper line (at frequencies above those already in use for POTS or even ISDN) and
