ADSL and VDSL faceplates perform similar functions but they are different.
The intention of both is to block the DSL frequencies from going onto the voice circuit and there is another filter in the modem which stops voice frequencies reaching the input stage. The faceplate filter should present a high impedance to everything in the DSL band.
However, the original ADSL filters were only designed and tested to the limits of ADSL which is just over 2MHz. VDSL started using frequencies up to 8MHz and most filters would probably cope. As VDSL moved up to higher frequencies, 12, 17 and 30 MHz then the performance of the original ADSL filters cannot be guaranteed and quite often they perform very badly at the higher frequencies either introducing phase anomalies or a low impedance which significantly attenuates the signal.
If you have a long line, an ADSL filter may be OK but if you are looking at maximum data rates/throughput then a decent VDSL filter is essential.
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M H C
taurus excreta cerebrum vincit
Edited by MHC (Thu 09-Jan-14 14:26:43)