OK Let's make cables:

Making patch cables is not easy! It take practice and patience. You will normally purchase patch cables but most companies expect you to know how to make one when needed.

You are going to make 3 cables

a straight patch cable

a crossover cable

a roll over cable (this is a serial cable for routers and switches)

This is the typical wiring standard used in most companies!

T568B
	Pin #	Conductor Color Code
	1	white/orange
	2	orange
	3	white/green
	4	blue
	5	white/blue
	6	green
	7	white/brown
	8	brown

Hold the wire near the RJ-45 plug with the clip down and firmly push it into the left side of the front of the crimper (it will only go in one way). Hold the wire in place squeeze the crimper handles quite firmly. This is what will happen:

(Crimp it once.) The crimper pushes two plungers down on the RJ-45 plug. One forces what amounts to a cleverly designed plastic plug/wedge onto the cable jacket and very firmly clinches it. The other seats the "pins," each with two teeth at its end, through the insulation and into the conductors of their respective wires.

8. Test the crimp... If done properly an average person will not be able to pull the plug off the cable with his or her bare hands. And that quite simply, besides lower cost, is the primary advantage of twisted-pair cables over the older thinwire, coaxial cables. In fact, I would say the RJ-45 and ease of its installation is the main reason coaxial cable is no longer widely used for small Ethernets. But, don't pull that hard on the plug. It could stretch the cable and change its characteristics. Look at the side of the plug and see if it looks like the diagram and give it a fairly firm tug to make sure it is crimped well.

How to wire your own ethernet cables and connectors.

What You Need:

Required:

CAT 5 Cable - bulk Category 5, 5e or 6 cable
RJ45 Ends
Crimper for RJ45
Wire Cutters - to cut and strip the cable if necessary

Recommend:

Wire Stripper
Cable Tester

About the Cable:

You can find bulk supplies of the cable at many computer stores or most electrical or home centers. You want UTP (Unshielded Twisted Pair) Category 5 cable for basic 10/100 functionality. You need CAT 5e for gigabit (1000BaseT) operation and CAT 6 gives you a measure of future proofing. Bulk cable comes in many types, there are 2 basic categories, solid and braided cable. Braided cable tends to work better in "patch" applications for desktop use. It is more flexible and resiliant than solid cable and easier to work with, but really meant for shorter lengths. Solid cable is meant for longer runs in a fixed position. Plenum rated cable should/must be used whenever the cable travels through an air circulation space. For example, above a false celing or below a raised floor.

You're likely going to want braided type cable but it may be difficult or impossible to tell from the box.

Here is what the internals of the cable look like:

cat 5 cable
Internal Cable Structure and Color Coding

Inside the cable, there are 8 color coded wires. These wires are twisted into 4 pairs of wires, each pair has a common color theme. One wire in the pair being a solid or primarily solid colored wire and the other being a primarily white wire with a colored stripe (Sometimes cable doesn't have any color on the striped cable, the only way to tell is to check which other wire it is twisted around). Examples of the naming schemes used are: Orange (alternatively Orange/White) for the solid colored wire and White/Orange for the striped cable. The twists are extremely important. They are there to counteract noise and interference. It is important to wire according to a standard to get proper performance from the cable. The TIA/EIA-568-A specifies two wiring standards for a 8-position modular connector such as RJ45. The two wiring standards, T568A and T568B vary only in the arrangement of the colored pairs. Tom writes to say "...sources suggest using T568A cabling since T568B is the AT&T standard, but the US Government specifies T568A since it matches USOC cabling for pairs 1 & 2, which allows it to work for 1/2 line phones...". Your choice might be determined by the need to match existing wiring, jacks or personal preference, but you should maintain consistancy. I've shown both below for straight through cabling and just T568B for cross over cabling.

About the RJ45 Ends:

The RJ45 end is a 8-position modular connector that looks like a large phone plug. There are a couple variations available. The primary variation you need to pay attention to is whether the connector is intended for braided or solid wire. For braided/stranded wires, the connector has contacts that actually pierce the wire. For solid wires, the connector has fingers which pierce the insulation and make contact with the wire by grasping it from both sides. The connector is the weak point in an ethernet cable, choosing the wrong one will often cause grief later. If you just walk into a computer store, it's nearly impossible to tell what type of connector it is.

Here is a diagram and pinout:

rj45 jack pinout
RJ45 Jack and Plug Pinout

Ethernet Cable Pinouts:

There are two basic cables. A straight through cable, which is used to connect to a hub or switch, and a cross over cable used to operate in a peer-to-peer fashion without a hub/switch. Some interfaces can cross and un-cross a cable automatically as needed, really quite nice.

Standard, Straight-Through Wiring (both ends are the same):

RJ45 Pin #	Wire Color (T568A)	10Base-T Signal 100Base-TX Signal	1000Base-T Signal
1	White/Green	Transmit+	BI_DA+
2	Green	Transmit-	BI_DA-
3	White/Orange	Receive+	BI_DB+
4	Blue	Unused	BI_DC+
5	White/Blue	Unused	BI_DC-
6	Orange	Receive-	BI_DB-
7	White/Brown	Unused	BI_DD+
8	Brown	Unused	BI_DD-

Straight-Through Cable Pinout for T568A

RJ45 Pin #	Wire Color (T568B)	10Base-T Signal 100Base-TX Signal	1000Base-T Signal
1	White/Orange	Transmit+	BI_DA+
2	Orange	Transmit-	BI_DA-
3	White/Green	Receive+	BI_DB+
4	Blue	Unused	BI_DC+
5	White/Blue	Unused	BI_DC-
6	Green	Receive-	BI_DB-
7	White/Brown	Unused	BI_DD+
8	Brown	Unused	BI_DD-

Straight-Through Cable Pinout for T568B

Cross Over Cable (T568B):

RJ45 Pin # (END 1)	Wire Color	Diagram End #1
1	White/Orange
2	Orange
3	White/Green
4	Blue
5	White/Blue
6	Green
7	White/Brown
8	Brown

RJ45 Pin # (END 2)	Wire Color	Diagram End #2
1	White/Green
2	Green
3	White/Orange
4	White/Brown
5	Brown
6	Orange
7	Blue
8	White/Blue

Cross Over Cable Pinouts

+Note: The cross over cable layout is suitable for 1000Base-T operation, all 4 pairs are crossed.

How to wire Ethernet Cables:

Strip off about 2 inches of the cable sheath.
Untwist the pairs - don't untwist them beyond what you have exposed, the more untwisted cable you have the worse the problems you can run into.
Align the colored wires according to the diagrams above.
Trim all the wires to the same length, about 1/2" to 3/4" left exposed from the sheath.
Insert the wires into the RJ45 end - make sure each wire is fully inserted to the front of the RJ45 end and in the correct order. The sheath of the cable should extend into the RJ45 end by about 1/2" and will be held in place by the crimp.
Crimp the RJ45 end with the crimper tool
Verify the wires ended up the right order and that the wires extend to the front of the RJ45 end and make good contact with the metal contacts in the RJ45 end.
Cut the cable to length - make sure it is more than long enough for your needs. Remember, an end to end connection should not extend more than 100m (~328ft). Try to keep cables short, the longer the cable becomes the more it may affect performance, usually noticable as a gradual decrease in speed and increase in latency.
Repeat the above steps for the second RJ45 end.
If a cable tester is available, use it to verify the proper connectivity of the cable.

That should be it, if your cable doesn't turn out, look closely at each end and see if you can find the problem. Usually a wire ended up in the wrong place or more commonly, one of the wires didn't extend to the front of the RJ45 connector and is making no, or poor contact. If you see a mistake or problem, cut the end off and start again.

Notes:

Power over Ethernet (PoE)

Power over Ethernet has been implemented in many variations before IEEE standardized 802.3af. 802.3af specifies the ability to supply an endpoint with 48V DC at up 350mA or 16.8W. The endpoint must be capable of receiving power on either the data pairs (often called phantom power) or the unused pairs in 100Base-TX. PoE can be used with any ethernet configuration, including 10Base-T, 100Base-TX and 1000Base-T. Power is only supplied when a valid PoE endpoint is detected by using a low voltage probe to look for the PoE signature on the endpoint. PoE power is typically supplied in one of two ways, either the host ethernet switch provides the power, or a "midspan" device is plugged in between the switch and endpoints which supplies the power.

RJ45 Pin #	Wire Color (T568A)	10Base-T Signal 100Base-TX Signal	PoE
1	White/Green	Transmit+	Mode A +
2	Green	Transmit-	Mode A +
3	White/Orange	Receive+	Mode A -
4	Blue	Unused	Mode B +
5	White/Blue	Unused	Mode B +
6	Orange	Receive-	Mode A -
7	White/Brown	Unused	Mode B -
8	Brown	Unused	Mode B -

Power over Ethernet Pinout

Protocol Details:

	Frequency (MHz)	Symbol Encoding	Signal Rate (Mbaud)	Symbol Rate	Data Encoding	Data Bits per Symbol	Pairs per Channel	Pairs Used	Minimum Cable Category
10BaseT	10	Manchester	10	10	None	1	1	2	3
100BaseT4	12.5	Multi-level, 2T/Hz	25	25	8B6T	8/6	3	4	3
100BaseTX	31.25	MLT-3	125	125	4B5B	4/5	1	2	5
100BaseT2	12.5	PAM5x5 (2D-PAM5)	25	12.5	None	4 (2x2)	2	2	3
1000BaseT	31.25	4D-PAM5	125	31.25	None	8 (4x2)	4	4	5*

*Designed to work on MOST category 5 cable, category 5e specifications ensure 1000Base-T operation

Cable Category Details:

Cable Category	Rated Frequency Bandwidth (MHz)	Common Uses
1	None
2	1	Telephone Wiring
3	16	Telephone Wiring, 10Base-T
4	20	Token-Ring, 10Base-T
5	100	100Base-TX, 10Base-T
5e	100	1000Base-T, 100Base-TX, 10Base-T
6	250	1000Base-T, 100Base-TX, 10Base-T

Increasing category levels are backward compatible.
Manufacturers will often test and certify their cable well beyond the standards

How to Make a Category 5 / Cat 5E Patch Cable

Due to an overwhelming response to our category 5 & 6 tutorial, and many requests for information and wiring diagrams of "straight through" and "crossover" (cross-pinned) patch cords, I have made this informational page. On this page, we will cover making patch cords, and other technical and non-technical issues relating to category 5 (and beyond) patching and connectivity from device to device. Below, you will find the diagrams for 568A, 568B, and crossover patch cables. I suggest that you read on, past the diagrams for some very useful and important information.

As always, there continues to be Controversies over standards and practices regarding the use and making of patch cords, and UTP cable in general. Please see our section below titled: "Controversies and Caveats : Category 5, 5E, and Cat 6 Patch Cables". I hope that you will find it interesting and informative.

568-B Wiring

Pair #	Wire	Pin #
1-White/Blue	White/Blue	5
1-White/Blue	Blue/White	4
2-Wht./Orange	White/Orange	1
2-Wht./Orange	Orange White	2
3-White/Green	White/Green	3
3-White/Green	Green/White	6
4-White/Brown	White/Brown	7
4-White/Brown	Brown/White	8
< 568-B Diagram

568-A Wiring

Pair #	Wire	Pin #
1-White/Blue	White/Blue	5
1-White/Blue	Blue/White	4
2-White/Green	White/Green	1
2-White/Green	Green/White	2
3-White/Orange	White/Orange	3
3-White/Orange	Orange/White	6
4-White/Brown	White/Brown	7
4-White/Brown	Brown/White	8
< 568-A Diagram

Notes for wiring diagrams above:

1. For patch cables, 568-B wiring is by far, the most common method.
2. There is no difference in connectivity between 568B and 568A cables. Either wiring should work fine on any system*. (*see notes below)
3. For a straight through cable, wire both ends identical.
4. For a crossover cable, wire one end 568A and the other end 568B.
5. Do not confuse pair numbers with pin numbers. A pair number is used for reference only (eg: 10BaseT Ethernet uses pairs 2 & 3). The pin numbers indicate actual physical locations on the plug and jack.

Patch Cable Assembly Instructions

1. Skin off the cable jacket approximately 1" or slightly more.
2. Un-twist each pair, and straighten each wire between the fingers.
3. Place the wires in the order of one of the two diagrams shown above (568B or 568A). Bring all of the wires together, until they touch.
4. At this point, recheck the wiring sequence with the diagram.
5. Optional: Make a mark on the wires at 1/2" from the end of the cable jacket.

6. Hold the grouped (and sorted) wires together tightly, between the thumb, and the forefinger.
7. Cut all of the wires at a perfect 90 degree angle from the cable at 1/2" from the end of the cable jacket. This is a very critical step. If the wires are not cut straight, they may not all make contact. We suggest using a pair of scissors for this purpose.

7B. Conductors should be at a straight 90 degree angle, and be 1/2" long, prior to insertion into the connector.

8. Insert the wires into the connector (pins facing up).

9. Push moderately hard to assure that all of the wires have reached the end of the connector. Be sure that the cable jacket goes into the back of the connector by about 3/16".

9. Place the connector into a crimp tool, and squeeze hard so that the handle reaches it's full swing.

10. Repeat the process on the other end. For a straight through cable, use the same wiring. For a "crossover" cable, wire one end 568A, and the other end 568B.
11. Use a cable tester to test for proper continuity.

Notes Regarding Making Category 5 Patch Cable

1) The RJ-45 plugs are normally made for either solid conductors or stranded conductors. It is very important to be sure that the plug that you use matches the conductor type. It is extremely difficult to tell the difference between the two by looking at them. When you buy these plugs, be sure to categorize, and store them carefully. Using the wrong type can cause intermittent problems. The RJ-45, 8 Conductor Plugs that we sell are rated for both Solid and Stranded cable.

2) Ordinarily, it would be taboo to untwist the pairs of any category 5 cable. The one exception to this rule is when crimping on RJ-45 plugs. It would be impossible to insert the wires into the channels without first untwisting and straightening them. Be sure not to extend the un-twisting, past the skin point. If you do it properly, you will wind up with no more than 1/2" of untwisted conductors (up to 1/2" of untwist meets the cat 5 specification).

3) If the completed assembly does not pass continuity, you may have a problem in one, or both ends. First try giving each end another crimp. If that does not work, then carefully examine each end. Are the wires in the proper order? Do all of the wires fully extend to the end of the connector? Are all of the pins pushed down fully. Cut off the suspected bad connector, and re-terminate it. If you still have a problem, then repeat the process, this time giving more scrutiny to the end that was not replaced.

4) It is good to be prepared to make your own patch cables. There may be many instances where you may fall short on supply, and making a cable will surely get you out of a jam. However, there comes a point where the practicality curve will lead you to factory made cables. Making several cables can be very labor intense. Factory made cables typically have better tolerances, and consequently have better quality than field made cables.

Controversies and Caveats: Category 5, 5E, and Cat 6 Patch Cables

568B vs. 568A

For patch cables, 568-B wiring is by far, the most common wiring method. Virtually all pre-assembled patch cables are wired to the B standard. There is no difference in connectivity between 568B and 568A cables. Therefore, a 568B patch cable should work fine on a 568A cabling system, and visa-versa. To my knowledge, there has never been an issue with networks of up to 100 megabits.

However, with the advent of Gigabit over copper cabling, it may very well become a factor at some point. We have conferred with several cable manufacturers, and many other technical resources, on this subject. The consensus is that mixing of the standards on patch cables should not cause a problem. Since Gigabit networks over copper cabling are in their infancy, and no one can say for sure, we would advise our customers to take the safe approach on all future patch cable orders. We now offer our custom cat 5E and category 6 cables in both 568A and 568B wiring schemes for this reason.

Re-use of old cables

We have seen this happen time and time again. Perfectly good patch cables that have been working fine for years, get removed from their installation, and re-installed on the same, or different network. The result can be a nightmare. What happens is that the cable, over time, adapts to the way that it is bent in it's original installation. When these cables are removed and re-installed, they can either completely loose their connection, or develop intermittent problems. This is due to stresses that may be opposite to what they were originally subject to. If the integrity of your network is more valuable than the price of new patch cables, then we strongly suggest that you use brand new cables for all closet cleanups, network moves, etc.

Stranded vs. Solid wire

Almost all patch cables that are made have stranded wire. Stranded wire is normally specified for use in patch cables due to it's superior flexibility. There has been some talk recently, in the technical sector of the structured wiring community, regarding the possible use of solid conductors for patch cables. The reason for the spotlight on solid wire is that it is supposedly more stable, under a variety of conditions. Please note that we now offer custom solid copper category 5E patch cables in Plenum insulation in lengths of up to 295 feet. These cables are suitable for use in air handling (Plenum) ceilings and environments.