If doubtful about ie or ei, when the seem with the vowel is as in brief /i:/, we spell it ie; but once the letter c, we spell it ei:Phase four: HDSL2 was created in 2000 to attain the identical data level and line selection as HDSL utilizing just one set of wiring instead of The 2 pairs wanted by HDSL. Equally HDSL and HDSL2 use CSA (provider servi