3Com 5112M-TPLS installation and operation guide Patch Panels, 2. Unshielded Twisted Pair Network

Figure 2-2. Unshielded Twisted Pair Network

While there is no fiber in the configuration in Figure 2-2, you can calculate the fiber equivalent distance as follows:

Total link distance: 100 m + 100 m + 100 m + 50 m + 20 m = 370 m

Total equivalent distance of the Security Modules: (4 * 420 m) + (4 * 165 m) =

2340 m (signal externally enters four Twisted Pair Modules: 4 * 420m)

(signal enters four Twisted Pair Modules from the backplane: 4 * 165 m)

Total equivalent distance: 370 m + 2340 m = 2710 m

Since the total equivalent distance (2710 m) is less than 4200 meters, this example is a legitimate configuration.

Patch Panels

Patch panels weaken signals that pass through them, thereby reducing achievable link distances. 3Com assumes the use of one patch panel in the 100 meter link distance calculations specified in this manual. However, each additional patch panel in the link reduces the 100 meter link distance by approximately 10 meters.

Designing and Expanding the Network 2 - 11