If the length of the fiber optic cable between TCF-142 devices is 20 km, you can connect up to 5 (five) TCF-142 devices to the network; if the fiber optic cable length is 2 km, up to 50 (fifty) TCF-142 devices can be connected to the network.
When designing an optical fiber ring network with TCF-142 Series devices that are configured in the Ring mode, the most important consideration is ensuring that data is not transmitted repeatedly through the network. A data-discard interval is set in all the TCF-142 device so that duplicate data received within that interval is discarded. The data-discard interval is set to 500* μs for all TCF-142 devices.
* When measuring the data transmission rate on a 25-km optical fiber network, we found that there is a 120 μs delay when the data travels from one end of the network to the other end. In addition, the data latency attributed to the TCF-142 device itself is 1 μs. To be able to meet the requirement of discarding duplicate data within the preset 500 to 550 μs, interval, the total length of the optical fiber cable should be less than 100 km.