I have an old but full and detailed pdf spec from B3 cable solutions for external 2 pair drop wire compliant with BT spec CW1411.
Snap!
I see that the electrical characteristics of CW1411 cable are stated to be --
- Maximum Conductor Resistance: 95 Ohms per km
- Maximum Mutual Capacitance: 56 nF per km
- Maximum Capacitance Unbalance: 275 pF per 500 m
- Minimum Insulation Resistance: 10,000 Mega Ohms per km
I suppose there is some logical reason why the maximum capacitive unbalance is stated as 275 pF per 500 metres rather than 550 pF per km . . .