BT reference number CW1308 specification twisted pair telephone cable. Solid tinned annealed copper cable suitable for ADSL & normal telephone use. 2 pairs, white outer insulation. INDOOR USE. Use 5mm cable clips. Sold by the metre.
Attenuation will be worse in Copper Clad Aluminium cables due to the higher bulk resistance of aluminium. This provides the risk of greater data loss, as more packets have to be retransmitted. Only use pure copper cable!