percentage of lines per card that are close to be optimal for the allocated v bat range of the card and v a b ring of the lines it can be possible to expand the analysis graphical presentation to shelf rack site levels or any portion geographical scale of an access network to suggest if at least two cards or other modules exist in the analyzed network portion the system is adapted to propose suggest more efficient line allocation schemes per card and in the analogous manner per shelf rack site etc e g the system is operative to recommend grouping of the subscriber lines according to common length categories so that the best suitability to v bat range be reached the system may also suggest changing adjusting the v bat range per module card the system is also adapted to propose suggest more efficient or optimal values of v a b ring for specific subscriber 39 s lines located on a single or plurality of line modules the basic embodiment of the proposed method system concerns plain old telephone service pots interfaces fig1 u2014 illustrates a conventional access network 10 connected to a packet network 12 which comprise elements that enable applying the proposed power saving technique the following clauses refer to reference numerals and detail functions of the elements which will be relevant to our further description subscriber interface 14 u2014 pots i f comprises of a 2 wire subscriber 39 s line pots line 16 18 20 and a terminal equipment customer premises equipment te cpe such as telephone set fax machine 15 17 19 etc the line and cpe together form a loop which is characterized by ohmic resistance and when at off hook.