Brocade 6910 Ethernet Access Switch Hardware Installation Guide
Brocade 6910 Ethernet Access Switch Hardware Installation Guide
2.2.0.0
Part Number: 53-1002650-01
documentation@brocade.com


Cables : Twisted-Pair Cable and Pin Assignments

Twisted-Pair Cable and Pin Assignments
For 10/100BASE-TX connections, the twisted-pair cable must have two pairs of wires. For 1000BASE-T connections the twisted-pair cable must have four pairs of wires. Each wire pair is identified by two different colors. For example, one wire might be green and the other, green with white stripes. Also, an RJ-45 connector must be attached to both ends of the cable.
* CAUTION: DO NOT plug a phone jack connector into any RJ-45 port. Use only twisted-pair cables with RJ-45 connectors that conform with FCC standards.
* CAUTION: Caution: Each wire pair must be attached to the RJ-45 connectors in a specific orientation.
The figure below illustrates how the pins on the RJ-45 connector are numbered. Be sure to hold the connectors in the same orientation when attaching the wires to the pins.
Figure 22 RJ-45 CONNECTOR PIN NUMBERS
10BASE-T/100BASE-TX Pin Assignments
Use unshielded twisted-pair (UTP) or shielded twisted-pair (STP) cable for RJ-45 connections: 100-ohm Category 3 or better cable for 10 Mbps connections, or 100-ohm Category 5 or better cable for 100 Mbps connections. Also be sure that the length of any twisted-pair connection does not exceed 100 meters (328 feet).
The RJ-45 ports on the switch base unit 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. In straight-through cable, pins 1, 2, 3, and 6, at one end of the cable, are connected straight through to pins 1, 2, 3, and 6 at the other end of the cable. When using any RJ-45 port on this switch, you can use either straight-through or crossover cable.
 
NOTE: The “+” and “-” signs represent the polarity of the wires that make up each wire pair.
Straight-Through Wiring
If the twisted-pair cable is to join two ports and only one of the ports has an internal crossover (MDI-X), the two pairs of wires must be straight-through. (When auto-negotiation is enabled for any RJ-45 port on this switch, you can use either straight-through or crossover cable to connect to any device type.)
You must connect all four wire pairs as shown in the following diagram to support Gigabit Ethernet.
Figure 23 STRAIGHT-THROUGH WIRING
Crossover Wiring
If the twisted-pair cable is to join two ports and either both ports are labeled with an “X” (MDI-X) or neither port is labeled with an “X” (MDI), a crossover must be implemented in the wiring. (When auto-negotiation is enabled for any RJ-45 port on this switch, you can use either straight-through or crossover cable to connect to any device type.)
You must connect all four wire pairs as shown in the following diagram to support Gigabit Ethernet.
Figure 24 CROSSOVER WIRING
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).
 
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.
2.
3.
Fiber Standards
The International Telecommunication Union (ITU-T) has standardized various fiber types for data networks. These are summarized in the following table.
 
Table 8
 
 
 

Cables : Twisted-Pair Cable and Pin Assignments