Cisco Networking Academy Del Mar College
ITNW 1425 - Fundamentals of Networking

Prof. Michael P. Harris, CCNA, CCAI
Cisco Semester 1 LABS

[Top] EIA/TIA-568-A Wiring Standard
T568A_Wiring.gif The EIA/TIA-568-A standard specifies two wiring schemes to be employed in Category 3-5 UTP installations. The difference between the T568A and T568B schemes is that pairs 2 and 3 are reversed. Although 10BaseT only needs two pair (pins 1,2,3,& 6), all four pairs must be terminated in either the T568A or T568B scheme. The T568B scheme is the most popular. The color scheme should be consistent throughout the system. The new 100Base-TX (IEEE 802.3u) uses the same wiring scheme as 10BaseT (pairs 2 and 3) over Category 5 UTP.

[Top] Paired Wiring (T568) Faults
Paired Wiring Faults

[Top] Project #1 - Patch Panels & 110 punch-down cabling

patch panel Click Me! Category 5 patch panels are EIA 19” rack mountable and available in either 12, 24, 36, 48 or 96-port models. Front RJ-45 jacks are connected to rear 110 terminals via a printed circuit board. The most popular wiring scheme is T568B. The 110 terminals are color coded and the circuit board displays the RJ-45 pin out at each 110 punch point.

[Top] Network Cable Tester
Cable Tester Use a network cable tester (also known as a patch cable tester) with the remote to test the continuity of individual cable pairs. In auto mode, the test sequences run automatically. Whereas the test pushbutton controls the sequencing of the test in the manual mode. The universal testers will senses paired and non-paired wiring faults. The master is used with the remote when both cable ends are not accessible at the same location. It also can be used as a bench tester for patch and jumper cables. Most models accept both RJ-45 and RJ11 plugs. Some models have an on/off switch to prevent activating the tester when it is not in use. Some models also include a pair of RJ-45/BNC jack adapter cables; BNC plug-to-plug adapter for testing coax cables; and RJ-45 flat silver satin cable.

[Top] Project #2 - 10BaseT/100Base-TX patch-cable

Technically, as long as you build your 10Base-T/100Base-TX patch-cable with straight-through connections for pairs 1 & 2 and 3, & 6 it will work. But there are EIA/TIA 568 standards that specifies minimum recommendations for telecommunications wiring within a structure, including telecommunication outlets, and between structures in a campus environment. It specifies a wiring system with a recommended topology and distances. It specifies media by parameters which determine performance and specifies connectors and their pin assignments to ensure interconnectability.

EIA/TIA T568B       EIA/TIA T568A

Using the USOC/PDS wiring pair color codes and the EIA/TIA T568B (AT&T 258A) wiring scheme assemble a standard 10BaseT cable with straight-through wiring using pins 1, 2, 3, & 6. Use a Network Cable Tester (patch cable tester) to insure connection integrity.

usoc Universal Service Ordering Codes (USOC): are a series of Registered Jack (RJ) wiring configurations developed by the Bell System for connection of customer premise equipment to the public network.

[Top] Banded & Solid / Wiring Pair color Codes:

Pair # ID Pin #
Pin #
1 T1 5 White/Blue 5 Red
R1 4 Blue(White) 4 Green
2 T2 1 White/Orange 6 Black
R2 2 Orange(White) 3 Yellow
3 T3 3 White/Green 7 Orange
R3 6 Green(White) 2 Blue
4 T4 7 White/Brown 8 Slate
R4 8 Brown(White) 1 Brown

[Top] UTP Tech Notes:

  • UTP Cable Stripping
    utp cable stripping The UTP cable's jacket is not exactly  round in shape. Since it is impossible to strip the jacket completely without nicking the inner conductors, adjust the jacket cutting blades so it only partially scores the jacket. Bending and twisting the jacket at the score will complete the strip.

  • UTP Cable Pulling
    Avoid stretching UTP cable. Pulling tension should not exceed 110N (25 lbf) for 4-pair cable. Also the bend radius of 4-pair UTP cable should not exceed 4 times the cable diameter. When cable ties are used, install them loosely.

  • UTP Cable Termination
    UTP cable pair twists must be maintained and untwisting must not exceed 0.5 inches when installing Category 5 plugs and jacks and when punching down into a 110 block. The cable jacket should only be stripped back 0.5 inches for the plug and be held by the plug's primary latching strain relief when crimped.

[Top] RJ-45 Modular Plugs
The RJ-45 modular plug was originally designed for silver satin cable with stranded conductors and used for voice applications. Since all conductors are side by side, this flat cable is easily stripped and crimped into the plug. The conventional plug has in-line insulation displacement contacts that pierce the middle of the insulation and stranded wire when crimped as illustrated in Fig. 1. RJ-45 plugs designed for solid conductors have offsetting contacts that straddle and wedge the cable’s solid conductor (Fig.2). If a RJ-45 plug designed for stranded conductors is crimped onto solid conductors, the blade’s piercing teeth will be deflected and bent by the cable’s center conductors resulting in an intermittent connection. However, the newer tri-point plugs are designed for both stranded and solid conductors and will successfully terminate both types of conductors. NOTE: AMP® RJ-45 plugs shown in Fig. 3 have a differently spaced secondary strain relief cavity. The industry standard crimp die with both primary (A) and secondary (B) cable strain relief indenters will cause damage to the AMP® RJ-45 brand plug or tool because of this non-alignment. for stranded utp for solid utp
RJ-45 modular plugs
RJ-45 Plugs  
CAT5 RJ-45 modular plug contacts have 50 micro” of gold plating, compliant with FCC Part 68, Subpart F requirements. The RJ-45 plug has an oval cable opening suitable for both round and flat cable. Although the RJ-45 plug is primarily designed for solid conductors, it will successfully terminate both solid and stranded conductors. Most RJ-45 plugs are compatible with most industry standard crimp tools except AMP tools.

[Top] Project #3 - 10BaseT/100Base-TX Cross-cable

To direct-connect two 10BaseT NIC's for testing or trouble shooting you will assemble a 10BaseT/100Base-TX cross-cable (sometimes called a UTP null-modem cable or plug-to-jack cable). This cable will allow you to connect two 10BaseT or 100Base-TX nodes together without the need for a concentrator. This can create a two-node LAN. Be sure to check the wiring with the Patch Check test tool.

Ethernet cross-cable

Category 5 Cross-Over Cables
cross over chart Category 5 cross-over cables are used to connect hub-to-hub, adapter card-to-adapter card, and T568A-to-T568B applications.
For example, cross-over cables must be used in uplinking hubs and peer-to-peer applications such as interconnecting two PC’s with Windows or Linux.  Cross-over cables "cross"  the transmit pair (pins 1 & 2) to the receive pair (pins 3 & 6).

NOTE: Look carefully at the basic 10BaseT cross cable diagram. Now, imagine a cable fabricated as EIA/TIA 568B on one side {W/O, O, W/G, B, W/B, G, W/N, N}

EIA/TIA T568B (RJ-45 pinout)
1 2 3 4 5 6 7 8

... and T568A {W/G, G, W/O, B, W/B, O, W/N, N} on the other side

EIA/TIA T568A (RJ-45 pinout)
1 2 3 4 5 6 7 8

... what would you have? ... an Ethernet cross-cable!

[Top] Project #4 - Surface-mount 110 Box

110 surface mount box Category 5 surface mount jacks can be Keystone or printed circuit type that meet 100 MHz requirements. The 110 type connecting blocks are connected to the RJ-45 in accordance with the T568A/B standard. RJ-45 jack contacts have 50 micro” of gold plating. A tie wrap attached to the circuit board provides cable strain relief. Wall plates can have a double-sided adhesive pad for mounting; they may also be screw-mounted. Surface mount boxes may come in single or duplex models.

[Top] Project #5a - Roll-Over cable

Modular Plug & Jack Wiring Schemes:
USOC modular wiring Typically, modular patch cords are used for two basic applications: data and voice (phone, modem and fax). Normally data network patch cords are wired “straight-through” (pin 1 to pin 1, pin 2 to pin 2, etc.). Voice patch cords are wired “crossed” (pin 1 to pin 6/8, pin 2 to pin 5/7, etc.). The USOC scheme is used for voice and not data because poor transmission performance is experienced with this type of cable and scheme.

To connect to a Cisco router's console and/or auxiliary port you will need a RJ-45-to-RJ-45 roll-over cable (5a) and RJ-45-to-DB9F DTE Terminal adapter (5b). You can identify a roll-over cable by comparing the two RJ-45 modular ends of the cable. Holding the RJ-45 plugs side-by-side with the tab at the back, the wire connected to the pin on the outside of the left plug should be the same color as the wire connected to the pin on the outside of the right plug (ie. mirror image or 180 degrees different from each other). A roll-over cable reverses pair 1 (pins 4 & 5), pair 2 (pins 3 & 6), pair 3 (pins 2 & 7), and pair 4 (pins 1 & 8).

Using the thin, flat, modular cable and two RJ-45 plugs fabricate a roll-over cable by crimping the RJ-45 to one end using the standard USOC color codes. Then before crimping the other side "roll over" (flip 180 degrees) the RJ-45 plug.

Cisco Console Port Signaling and Cabling
Console PortRoll-Over Cable  Terminal Adapter Console Device
DTE SignalRJ-45 plug USOC colorRJ-45 plug RJ-45 jackT568 color DB9F pinDTE Signal
RTS1 Brown 88 slate 8CTS
DTR2 Blue 77 Brown 6DSR
TxD3 yellow 66 yellow 2RxD
GND4 Green 55 Green 5Signal Ground
GND5 red 44 red
RxD6 Black 33 Black 3TxD
DSR7 Orange 22 Orange 4DTR
CTS8 slate 11 Blue 7RTS

NOTE: On some modular cables/adapters, the slate conductor is White .

[Top] Project #5b - RJ-45/DB9F Terminal Adapter (Cisco console cable)

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