RJ-45 Crossover Cable and Straight Through Pinouts
Please Note: The standard connector view shown is color-coded for a straight thru cable assembly, when connecting Hub to Xcvr or DNI Card. When connecting hub to hub, Xcvr to Xcvr, or DNI to DNI, the wires must crossover at the opposite end of the cable assembly.
Interconnecting Your Hubs, Transceivers, and DNI Cards
As noted in the illustrations below, a crossover cable is required when connecting a Hub to a Hub, or a Transceiver to Transceiver, or DNI to DNI card, or Transceiver to DNI card. When connecting a Hub to a transceiver or DNI card, a straight through cable is always used. Please Note: Some Cabletron products are equipped with internal switches that can internally cross the twisted pairs.
In these illustrations a Hub can refer to any standalone product, such as the SEHI or MicroMMAC; or concentrator modules in MMAC-FNB or MMACPLUS hubs, such as a TPMIM-xx, TPRMIM-xx or 9E132-15. To note the differences between Ethernet, Token Ring and FDDI/ATM connectivity, refer to the Wiring Color Code Standards.
Hub to Hub Connectivity
Hub to Transceiver or DNI Card Connectivity
Transceiver to DNI Connectivity
Standard Ethernet Cable Part Numbers
Category 5 wiring standards:
EIA/TIA 568A/568B and AT&T 258A define the wiring standards and allow for two different wiring color codes.
100baseT Straight Cable (PC to HUB/SWITCH)
Straight cables are used to connect PCs or other equipment to a HUB or Switch. If your connection is PC to PC or HUB to HUB you MUST use a Crossed cable.
The following cable description is for the wiring of BOTH ends (RJ45 Male connectors) with your category 5 wiring colors (TIA/EIA 568A or 568B though the example uses 568B colors).
|Pin No.||strand color||Name|
|1||white and orange||TX_D1+|
|3||white and green||RX_D2+|
|5||white and blue||BI_D3- **|
|7||white and brown||BI_D4+ **|
We use BLUE for 100baseT straight cables.
NOTE 1: Wires marked ** are ABSOLUTELY NECESSARY for 100Base-T4 networks (using any combination of category 3/4/5 cables) but are not required for 100Base-TX (using cat 5/5e ONLY cables) and CAN be used for other purposes e.g. telephony
NOTE 2: All our wiring is now done to the 100baseT spec which you can use with 10baseT networks - but NOT the other way around.
100baseT Crossed cable (PC to PC or HUB to HUB)
Crossed cables are used to connect PCs to one other PC or to connect a HUB to a HUB. If your connection is PC to HUB you MUST use a Straight cable.
The following description shows the wiring at both ends (male RJ45 connectors) of the crossed cable.
We use RED for crossed cables (or more commonly now a red heat-shrink collar at each end). NOTE: All our crossed wiring is now done to the 100baseT spec which you can use with 10baseT networks - but NOT the other way around.
|GIGABIT ETHERNET (1000BASE-T) CROSSOVER|
|Plug A||Plug B|
|Pin #||Signal||Conductor Color Code||Pin #||Signal||Conductor Color Code|
|Legend: N/U - Not used. May be either short or open circuit|
In a rolled cable, the colored wires at one end of the cable are in the reverse sequence of the colored wires at the other end of the cable.the 8-port RJ-45 adapter that is used with the Cisco 2509, 2510, 2511, and 2512, is the same as a rolled cable