What is the supposed benefit of doing that?![]()
Most 10Mbps and higher ADSL2+ customers are unable to reach the maximum line speeds due to poor line characteristics. Each filter added to the line degrades the performance even further so it is recommended to install one central filter and connect all extensions to this rather than to supply each telephone with a separate filter. There are also large differences in the characteristics of the different filters as the link below shows. In many cases the linespeed can be increased by as much as 2Mbps or more by redoing the existing telephone wiring and installing a good quality central splitter/filter.
http://www.adslnation.com/support/filters.php