All the fiber-optic ports on the DeltaV Smart Switches, with the exception of the fiber-optic SFP transceivers, operate at 100 mb/s full duplex. Some switches on DeltaV networks, in particular some 3Com switches, operate at 100 mb/s half duplex. Duplex mismatch will result in unpredictable communications. Therefore, before connecting a DeltaV Smart Switch to a third-party switch using a fiber-optic uplink, configure the fiber-optic port of the other switch to operate at 100 mb/s full duplex. Be sure to save the configuration into permanent memory. Otherwise, the third-party switch may revert to the old configuration the next time it is rebooted. Additionally, the third-party switch may require a reboot after reconfiguring the switch and saving the configuration. Refer to the switch manufacturer's documentation for the proper method of making these changes. Refer to the DeltaV TM M-series Hardware Installation and Reference manual for information on third-party switches that can be used with a DeltaV system.
Do not connect a gigabit port of an SFP module to a 100 mb/s port of any switch. The SFP transceivers do not autosense speed and must be connected to a port with the same configured speed. That is, connect gigabit ports to gigabit ports and 100 mb/s ports to 100 mb/s ports. Additionally, all DeltaV Smart Switch twisted-pair ports are configured to autosense speed to 10 mb/s, 100 mb/s, or 1,000 mb/s and autonegotiate to half or full duplex depending on what they are connected to. Never connect a DeltaV Smart Switch's twisted-pair port to another type of switch with a hard-set twisted-pair port such as a port that is hard set to 100 mb/s full duplex. This will cause a duplex mismatch and unpredictable communications issues.