Just because a switch supports 100 Mbps doesn't mean it supports the real-time throughput that the data rate implies. Electrical noise Because the capabilities of Ethernet components vary widely, users must closely examine specifications, especially for immunity to electrical noise. To be considered electrically hardened, network components must have a high common mode of rejection, according to Mr. Lounsbury. Ethernet is typically a differential communication system that uses two wires to transmit and two wires to receive data. These are configured as a twisted pair, either unshielded or shielded.
Differential signaling helps increase immunity to electrical noise.
Manufacturers from several fields are seeking to solve these problems. JetLab from Jetter USA Inc. Cordsets consist of Category 5 cable. NetGateway helps users access plant-floor processes from office settings, while still keeping these networks separate. Also, though Ethernet isn't intrinsically safe yet, ISA's MLT committee is examining how to develop intrinsically safe fiber-optic cable for use in Ethernet networks.