B Cables
Table B-2 1000BASE-T MDI and MDI-X Port Pinouts
Pin | MDI Signal Name | MDI-X Signal Name |
4 | Bi-directional Data Four Plus (BI_D4+) | Bi-directional Data Three Plus (BI_D3+) |
| | |
5 | Bi-directional Data Four Minus (BI_D4-) | Bi-directional Data Three Minus (BI_D3-) |
| | |
6 | Bi-directional Data One Minus (BI_D1-) | Bi-directional Data Two Minus (BI_D2-) |
| | |
7 | Bi-directional Data Three Plus (BI_D3+) | Bi-directional Data Four Plus (BI_D4+) |
| | |
8 | Bi-directional Data Three Minus (BI_D3-) | Bi-directional Data Four Minus (BI_D4-) |
| | |
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.”
Note that when testing your cable installation, be sure to include all patch cables between switches and end devices.
Adjusting Existing Category 5 Cabling to Run 1000BASE-T
If your existing Category 5 installation does not meet one of the test parameters for 1000BASE-T, there are basically three measures that can be applied to try and correct the problem:
1.Replace any Category 5 patch cables with high-performance Category 5e or Category 6 cables.
2.Reduce the number of connectors used in the link.
3.Reconnect some of the connectors in the link.
Fiber Standards
The current TIA (Telecommunications Industry Association) 568-A specification on optical fiber cabling consists of one recognized cable type for horizontal subsystems and two cable types for backbone subsystems.
Horizontal 62.5/125 micron multimode (two fibers per outlet).
Backbone 62.5/125 micron multimode or single mode.
TIA 568-B will allow the use of 50/125 micron multimode optical fiber in both the horizontal and backbone in addition to the types listed above. All optical fiber components and installation practices must meet applicable building and safety codes.
