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HiSpeed Switch Troubleshooting Guide
4-2
US7070447-001, Rev 01
Draft Level—Hitachi Confidential
❒ Line transmission modes on the 10/100BASE-TX ports support both
half-duplex and full-duplex operations. By definition, the CSMA/CD
protocol is half-duplex where data can be transmitted and received in both
directions, but only at one direction at a time. Therefore, 10BASE-TX ports
operate in half-duplex mode only.
10BASE-TX Ports
The 10BASE-T port connections are provided for the 10 Mbps Ethernet segment
or nodes to attach to the HiSpeed switch. The RJ-45 jacks accept standard
Category 3, 4, or 5 copper unshielded twisted pair (UTP) cable connections. Pin
assignments for the standard RJ-45 connector are given in Table 4-1. The HiSpeed
switches are shipped with the 10BASE-T connectors configured as MDI-X
(media-dependent interface-crossover). These ports connect over straight cables
to the network interface controller (NIC) card in a node or server, similar to a
conventional Ethernet repeater hub. If you are connecting to another Ethernet hub
or Ethernet switch, you need a crossover cable unless an MDI connection exists
on the associated port of the attaching device (see “Connecting 10BASE-T Ports”
on page 2-8 for a description of the crossover cable).
The 10 Mbps ports operate in half-duplex mode only, and each port has an
associated LED that indicates link status of the line.
Table 4-1. RJ-45 Connector pin assignments
Pin MDI-X Signal
1 Receive data + (RD+)
2 Receive data - (RD-)
3 Transmit data + (TR+)
4 Not used
5 Not used
6 Transmit data - (TD-)
7 Not used
8 Not used