Cabletron Systems 42T User Manual

The fiber optic delay budget, which determines the fiber optic cable’s 
maximum length, should be calculated and taken into consideration in the 
network design stage. Fiber optic delay budget is determined by summing 
the optical signal loss due to fiber optic cable attenuation, in-line splices, 
and fiber optic connectors. 

Table 2-7 shows specifications for the Single Mode Fiber Optic Cable 
supported by TPIM-F3.

The maximum trunk cable length between the MicroMMAC-T and other 
active devices is equal to the Maximum Drive Distance as shown in 
Table 2-7. For passive devices, the combined length of twice the longest 
trunk cable plus the longest lobe cable attached to the passive ring segment 
must not exceed the Maximum Drive Distance Trunk Length.

Fiber optic cable must be tested with an attenuation test set adjusted for a 
1300 nm wavelength. This test ensures that the cable’s signal loss is within 
an acceptable range of 10 dB or less for any given single mode fiber optic 
link.

8/125-12/125 

µ

m

10.0 dB or less

The max. allowable fiber optic 
cable length is 10 km (10936 
yards). However, IEEE 802.5 
specs allow for a max. of 1 km 
(1093.6 yards).