the older wires are .6 mm2 copper. at one point they tried to save money by going to .4 mm2 aluminum for a few years. works for pots, but sucks for people that want dsl.they are back to copper since then, but they went to .4 copper before going back to .6 copper. lines with mixed edia are really bad for dsl, lol. i don't work there any more, i did a 3 year job training there. was cool, gave a lot of insight since you get passed around the different departments.