Method for determining the electrical cable length of an active ring of a token ring local area network

An apparatus for determining the cable length of a ring of a Token-Ring local area network, said apparatus comprising:

• a time for timing a ring propagation time required for a signal to pass through each station actively connected to said ring;
• means for determining an active monitor propagation delay for a signal to pass through an active monitor station connected to said ring;
• means for determining a station propagation delay for a signal to pass through a standby monitor station connected to said ring;
• a counter for counting a number of standby monitor stations actively connected to said ring;
• a multiplier circuit for multiplying said number of standby monitor stations by said station propagation delay to create a total station propagation delay;
• a circuit for subtracting said active monitor propagation delay and for subtracting said total station propagation delay from said ring propagation time to create a cable propagation delay;
• and
• a second multiplier circuit for multiplying said cable propagation delay by the speed of light and by a cable propagation constant to produce said cable length.