TWISTED-PAIR CABLE AND PIN ASSIGNMENTS
1000BASE-T Pin Assignments
All 1000BASE-T ports support automatic MDI/MDI-X operation, so you can use straight-through cables for all network connections to PCs or servers, or to other switches or hubs.
The table below shows the 1000BASE-T MDI and MDI-X port pinouts. These ports require that all four pairs of wires be connected. Note that for 1000BASE-T operation, all four pairs of wires are used for both transmit and receive.
Use 100-ohm Category 5, 5e or 6 unshielded twisted-pair (UTP) or shielded twisted-pair (STP) cable for 1000BASE-T connections. Also be sure that the length of any twisted-pair connection does not exceed 100 meters (328 feet).
Table B-2 1000BASE-T MDI and MDI-X Port Pinouts
Pin | MDI Signal Name | MDI-X Signal Name |
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1 | Bi-directional Data One Plus (BI_D1+) | Bi-directional Data Two Plus (BI_D2+) |
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2 | Bi-directional Data One Minus (BI_D1-) | Bi-directional Data Two Minus (BI_D2-) |
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3 | Bi-directional Data Two Plus (BI_D2+) | Bi-directional Data One Plus (BI_D1+) |
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4 | Bi-directional Data Three Plus (BI_D3+) | Bi-directional Data Four Plus (BI_D4+) |
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5 | Bi-directional Data Three Minus (BI_D3-) | Bi-directional Data Four Minus (BI_D4-) |
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6 | Bi-directional Data Two Minus (BI_D2-) | Bi-directional Data One Minus (BI_D1-) |
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7 | Bi-directional Data Four Plus (BI_D4+) | Bi-directional Data Three Plus (BI_D3+) |
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8 | Bi-directional Data Four Minus (BI_D4-) | Bi-directional Data Three Minus (BI_D3-) |
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Cable Testing for Existing Category 5 Cable
Installed Category 5 cabling must pass tests for Attenuation, Near-End Crosstalk (NEXT), and Far-End Crosstalk (FEXT). This cable testing information is specified in the ANSI/TIA/EIA-TSB-67 standard.
Additionally, cables must also pass test parameters for Return Loss and Equal-Level Far-End Crosstalk (ELFEXT). These tests are specified in the ANSI/TIA/EIA-TSB-95 Bulletin, “The Additional Transmission Performance Guidelines for 100 Ohm 4-Pair Category 5 Cabling.”
