The use of fiber media is common in applications that require connecting devices spread over large distances. Distances up to 2 km are common with multi-mode fiber while single-mode fiber can support distances of up to 15 km. Fiber also supports a higher bandwidth than copper media. For copper, the bandwidth and maximum speed depend on the type of Ethernet cable. A Cat5 Ethernet cable is limited to 100 Mbps and cannot support gigabit speeds over the full 100 m Ethernet segment. Using the fiber media as a backbone and using copper media to connect local devices is a standard practice.
There are two options for converting between copper and fiber. An Ethernet switch that has both copper and fiber ports can be used to convert between the two media. Another device that can be used is a media converter. At a first glance, it may seem that either a switch or a media converter can be used interchangeably. But there are some performance differences that influence the actual device selection.
An Ethernet Switch operates on the store-and-forward principle. A full packet is received and then transmitted out, introducing latency in the data transmission. This may be acceptable for some applications, but critical applications (motion control, for example) may be adversely impacted by this store-and-forward operation. A media converter, on the other hand, operates on the bit level sending them out to the other port as the bits are received. This eliminates the store-and-forward packet delay associated with using an Ethernet switch as the media converter device. It is important to select a true media converter device for time critical applications as some manufacturers simply label a two-port Ethernet switch as a media converter.
The EIMK Series of Media Converters from Contemporary Controls are true media converters, operating without the store-and-forward delays. Multi-mode and single-mode models are available with ST or SC connectors. The EIMK-100T/FCS model supports single-mode fiber via SC-style connectors. On the copper side, both MDI and MDIX ports are available to compliment either an end station port or a switch port. Link and activity LEDs allow troubleshooting on both the copper and fiber sides.
All units mount on TS-35 DIN-rail and operate from either a 24 VAC or DC power source while offering redundant power connections. Incorporating a half-wave rectifier design allows the power source to be shared with other half-wave devices. Designed for commercial and industrial Ethernet applications, all models comply with EMC immunity and emissions standards for industrial environments.
