Token Ring transmission media
The classic token ring with 4 Mbit/s or 16 Mbit/s uses the STP cable according to type 1 of the IBM cables as transmission medium. In token ring networks, the connectable cable length of the lobe cable depends on the transmission rate, the number of ring line distributors, the distribution spaces (wiring closet) and the adjusted ring length( ARL).
The permissible length of the lobe cable results from the values taken from the tables for 4 Mbit/s and 16 Mbit/s, minus the ARL.
Example: A 4 Mbit/s token ring LAN with 10 ring cable distributors and 5 distribution rooms has a max. distance of 280 m. If the averaged ring length is 200 m, the lobe cable can be 80 m long. All specifications refer to amplifierless token ring LANs.
The length determination for token ring LANs can also be made using the attenuation budgets of the ring line distributor and cable. The attenuation budget of the RLV is between 1.2 dB and 2.6 dB depending on the input/output combination, and the attenuation for the cable is 2.2 dB/100 m at 4 MHz for type 1 cable. The total attenuation budget is 26 dB. When using fiber optic cables with the corresponding converters, there is physically hardly any distance limitation, since the corresponding fiber optic converters can be cascaded as often as required.
In the 100 Mbit/s version, i.e. FDDI, fiber optic cables are used as transmission media.