A
agnivo007
Ribbed ones with glass-wool between them is used for outdoor transmission.Two-wired cubical (mostly black/silver) are used for connecting equipments to line. examples - line,splitter,modem,telephone.Cylindrical ones are mainly used for internal wiring.It's best to use the cables supplied with router/modem/tel. Shielded varieties are not available as far as phone cables are concerned !As for LAN cables, all cables available/supplied now are CAT5e cables. So, there's no need to worry. If cable is made personally (like me), please check that you use good quality CAT5e cable and best quality RJ45 connectors.LAN cable has no relation with buzz associated with tel. It is more while dialtone, decreases on connection. 