Verify proper installation and connection of communications cables. Be sure that the host computer operating system and associated applications programs have been properly loaded and started. If host communication is restored, service the standby controller. Physical Ethernet connections are determined by the network environment. Cables should be routed away from sources of EMI and RFI noise which might induce spurious signals.
Induced noise can cause erratic system performance, including loss of service.
Modems Modem setup parameters are dictated by the type of interface, communication protocol, cabling requirements, and answering mode required for the intended application. If the modems are connected over the switched public network or leased data lines, you must also contend with problems of noise, line losses, and other problems common to data communications over analog networks. Traffic throughput requirements affect the CPU overhead required in the host computer. The host computer must be loaded with appropriate communications software. O performance is controlled by the sophistication of the communications package running on the host.