29
NEED HELP?
LEAVE THE TECH TO US
LIVE 24/7
TECHNICAL
SUPPORT
1.877.877.2269
1.877.877.2269
BLACKBOX.COM
CHAPTER 9: CABLES
9.5 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 next table shows the 1000BASE-T MDI and MDI-X port pinouts. These ports require that all four pairs of wires be connected.
NOTE
: 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 9-2. 1000BASE-T MDI AND MDI-X PORT PINOUTS
PIN #
MDI SIGNAL NAME
MDI-X SIGNAL NAME
1
Bi-directional Pair A Plus (BI_DA+)
Bi-directional Pair B Plus (BI_DB+)
2
Bi-directional Pair A Minus (BI_DA-)
Bi-directional Pair B Minus (BI_DB-)
3
Bi-directional Pair B Plus (BI_DB+)
Bi-directional Pair A Plus (BI_DA+)
4
Bi-directional Pair C Plus (BI_DC+)
Bi-directional Pair D Plus (BI_DD+)
5
Bi-directional Pair C Minus (BI_DC-)
Bi-directional Pair D Minus (BI_DD-)
6
Bi-directional Pair B Minus (BI_DB-)
Bi-directional Pair A Minus (BI_DA-)
7
Bi-directional Pair D Plus (BI_DD+)
Bi-directional Pair C Plus (BI_DC+)
8
Bi-directional Pair D Minus (BI_DD-)
Bi-directional Pair C Minus (BI_DC-)
9.6 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.
9.7 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.
