15
6650-2260
The EIA-709.3 recommendation is strict and shall handle 100% load on a network,
decreasing the load gives possibility to increase the allowed delay in the network.
Westermo has made tests with 60% load on the TP/FT-10 network and up to 60% load it
is possible to increase the allowed delay to 127 µs.
The following relation can be used on networks with up to 60% load
Fibre distance (m) / 200 + Number of units < 127
Recommended max number of units = 10
For example, the above equation would allow 10 LRW-102 units to use a maximum fibre
optic cable length of 23.4 km (15 miles).
The above discussion considers the limitation in maximum distance due to protocol
parameters involving media access and network idle detection. As with all fibre optic
products, the maximum distance is also dependent on the over all power budget (see
page 17).
