GE GFK-1541B manual 10Base-T/100Base Tx Port

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10Base-T/100Base Tx Port

The Series 90-30 CPU374 Embedded Ethernet Interface has an embedded switch that provides two external ports, each of which supports both 10Base-T and 100Base Tx operation using either full duplex or half duplex operation. Each switch port auto-negotiates (by default) to the correct link speed and duplex mode for the device connected to the other end of the link. Each port operates independently, so devices at two different speeds and/or duplex modes may be attached to the two ports. Each port also automatically detects the attached cable and will work properly with either straight-through or crossover cables (by default).

Caution

The two Ethernet ports on the Ethernet Interface must not be connected, directly or indirectly, to the same device. The connections in an Ethernet network based on twisted pair cabling must form a tree and not a ring, otherwise duplication of packets and network overload may occur.

Caution

The IEEE 802.3 standard strongly discourages the manual configuration of duplex mode for a port (as would be possible using Advanced User Parameters). Before manually configuring duplex mode for a CPU374 port using advanced user parameters (AUP), be sure that you know the characteristics of the link partner and are aware of the consequences of your selection. Setting both the speed and duplex AUP’s on a CPU374 port will disable the port’s auto-negotiation function. If its link partner is not similarly manually configured, this can result in the link partner concluding an incorrect duplex mode. In the words of the IEEE standard: “Connecting incompatible DTE/MAU combinations such as full duplex mode DTE to a half duplex mode MAU, or a full-duplex station (DTE or MAU) to a repeater or other half duplex network, can lead to severe network performance degradation, increased collisions, late collisions, CRC errors, and undetected data corruption.”

The switch ports support both shielded and unshielded cables.

The 10Base-T/100Base Tx twisted pair cables must meet the applicable IEEE 802 standards.

This section provides the information you need to specify the 10Base-T/100Base Tx twisted pair cables, including port pinouts and cable diagrams.

B-8 TCP/IP Ethernet Communications for the Series 90™ PLC User's Manual– May 2002 GFK-1541B