| Construction |
2 cores, twisted, with common shield |
| Conductor cross section |
> 0.22 mm² (24 AWG) |
| Twisting rate |
> 10 per meter (symmetrically twisted) |
| Core insulation |
Polyethylene (PE) |
| Resistance per core |
< 100 Ω/km |
| Characteristic impedance |
ca. 120 Ω (100…150 Ω) |
| Capacitance between the cores |
< 55 nF/km (if higher, the max. bus length must be reduced) |
| Terminating resistors |
120 Ω ¼ W at both line ends |
| Remarks |
Commonly used telephone cables with PE insulation and a core diameter of > 0.8 mm are usually sufficient. |
| Cables with PVC core insulation and core diameter of 0.8 mm can be used up to a length of approx. 250 m. In this case, the bus terminating resistor is approx. 100 Ω. |
