Db25 Pinout Colors

A 10Base-T Cross-over swaps TD and RD.That is, swap pins 1 and 3 as well as pins 2 and 6, on one end of the cable. AT&T 258A wiring is comparable to T568B. RS232 pinout RS232 pinout standards exist for both DB9 and DB25 connectors as shown below: DB25 SIGNAL DB9 DEFINITION 1 Protective Ground 2 TXD 3 Transmitted Data 3 RXD 2 Received Data.

The 25-pair color code, originally known as even-count color code,^[1] is a color code used to identify individual conductors in twisted-pairwiring for telecommunications.

Color coding[edit]

With the development of new generations of telecommunication cables with polyethylene-insulated conductors (PIC) by Bell Laboratories for the Bell System in the 1950s, new methods were developed to mark each individual conductor in cables.^[2] Each wire was identified by the combination of two colors, one of which is the major color, and the second the minor color. Major and minor colors are chosen from two different groups, resulting in 25 color combinations. The color combinations are applied to the insulation that covers each conductor. Typically, one color was a prominent background color of the insulation, and the other was a tracer, consisting of stripes, rings, or dots, applied over the background. The background color always matches the tracer color of its paired conductor, and vice versa.

The major, or primary group of colors consists of the sequence of white, red, black, yellow, and violet. The minor, or secondary color was chosen from the sequence blue, orange, green, brown, and slate.^[3][4]

The wire pairs are referred to either directly by their color combination, or by the pair number. For example, pair 9 is also called the red-brown pair. In technical tabulations, the colors are often suitably abbreviated.

Violet is the standard name in the telecommunications and electronics industry, but it is sometimes referred to as purple. Similarly, slate is a particular shade of gray. The names of most of the colors were taken from the conventional colors of the rainbow or optical spectrum, and in the electronic color code, which uses the same ten colors, albeit in a different order.^{[citation needed]}

When used for POTS, the first wire is known as the tip or A-leg (U.K.) conductor and is usually connected to the positive side of a direct current (DC) circuit, while the second wire is known as the ring lead or B-leg (U.K.), and is connected to the negative side of the circuit. Neither of these two sides of the line has a connection to the local ground. This creates a balanced audio circuit with common-mode rejection, also known as a differential pair. The tip and ring convention is based on the ​¹⁄₄″ (6.5 mm) TRS phone connectors, which were employed in telephone switchboards in the 19th and 20th centuries, where the tip contact of the connector is separated from the ring contact by a spacer of insulation. The connection furthest from the cable is known as the tip, the middle connection is the ring, and the (largest) connection closest to the wire is the sleeve.

Older Bell System wiring inside customer premises used 4-conductor untwisted wire cable. The 4 conductors were solid red, green, yellow & black wires. They match to the current 25-color code as follows:

25-pair telco cable pinout[edit]

A common application of the 25-pair color code is the cabling for the Registered Jack interface RJ21, which uses a female 50-pin miniature ribbon connector, as shown in the following table. The geometry of the pins of the receptacle (right hand image) corresponds to the pin numbers of the table. The left column of pins are the ring (R) conductors, while all tip (T) conductors are on the right.

Larger cables[edit]

For cables with more than 25 pairs, each group of 25 is called a binder group. The binder groups are marked with mylar ribbons using the same color coding system, starting with a white/blue ribbon, then a white/orange ribbon, and so on. The 24th binder group has a violet/brown ribbon, completing a super binder of 600 pairs.^[3][4]

In cables of more than 600 pairs, each of the 600-pair binder group bundles is wrapped with a mylar binder ribbon, or string, matching the 'tip' colors of the color code, starting with white. The pattern then starts over with the first 25-pair group as white/blue, and continues indefinitely, in multiples of 600 pairs or parts thereof. For example, a 900-pair cable has the first 600 pairs in 24 groups of 25 pairs in a white binder, and the remaining 300 pairs in 12 groups of 25 pairs wrapped in a red binder.^[3][4]

Some cables are 'mirrored' or 'clocked' with a pattern that is known throughout the telephone industry. Starting with the first binder group in the center, the technician counts the cable's groups in a spiral direction depending on the location of the central office or switch. If looking at the cable's core and the switch is in that direction, the groups are counted counter-clockwise. If the cable is the field side, the count is clockwise. There are indicators on the mylar ribbons to know where to begin for each layer and a diagram for the different cable sizes should be readily available for reference.^[3][4]

Other color schemes are sometimes used for outdoor cables, particularly outside the U.S., but this color code is common for aerial and underground cables up to several thousand pairs in North America. In the UK, the British Post Office (later BT) used this color code for what is now known loosely as CW1308 specification cables, referring to the Post Office's 'Cable and Wire' specification No. 1308.

Extra pairs and colors[edit]

When working on aerial cable splicing and installation, it is common to use a telephone lineman's set or 'Butt Set' to communicate over long distances. To facilitate this, extra pairs of wires are embedded in cables. One extra pair (Red-White) may be embedded into cables that are 6 to 75 pairs; two pairs (Red-White and Black-White) may be encapsulated in cables of 100 to 300 pairs; and three pairs (Red-White, Black-White, and Yellow-White) may be included in cables of 400 to 900 pairs.^[4] These extra pairs are often referred to as 'talk pairs', and are never used to deliver dial tone.

Optical fiber cables use a twelve-color code, where the first ten are the same as in the 25-pair color code, and the last two are Rose and Aqua.^[5]

Memorizing the colors[edit]

Various mnemonics have been used to remember the color coding of the major color groups and the minor color groups:

Db25 Pinout Color Code

Why Run Backwards, You'll Vomit - White-Red-Black-Yellow-Violet^[6]

Bell Operators Give Better Service - Blue-Orange-Green-Brown-Slate^[7] Adobe acrobat 7.0 professional serial number.

See also[edit]

When working on aerial cable splicing and installation, it is common to use a telephone lineman's set or 'Butt Set' to communicate over long distances. To facilitate this, extra pairs of wires are embedded in cables. One extra pair (Red-White) may be embedded into cables that are 6 to 75 pairs; two pairs (Red-White and Black-White) may be encapsulated in cables of 100 to 300 pairs; and three pairs (Red-White, Black-White, and Yellow-White) may be included in cables of 400 to 900 pairs.^[4] These extra pairs are often referred to as 'talk pairs', and are never used to deliver dial tone.

Optical fiber cables use a twelve-color code, where the first ten are the same as in the 25-pair color code, and the last two are Rose and Aqua.^[5]

Memorizing the colors[edit]

Various mnemonics have been used to remember the color coding of the major color groups and the minor color groups:

Db25 Pinout Color Code

Why Run Backwards, You'll Vomit - White-Red-Black-Yellow-Violet^[6]

Bell Operators Give Better Service - Blue-Orange-Green-Brown-Slate^[7] Adobe acrobat 7.0 professional serial number.

See also[edit]

References[edit]

Db25 Pinout Colors Chart

1. ^AT&T, Bell System Practices, Section 461-200-101 Issue 7, Connector Cables—Identification (May 1979)
2. ^F.W. Horn, Even-Count Cable, Bell Laboratories Record 37(6), 208 (June 1959)
3. ^ ^abcdHighhouse, John (1997). A Guide for Telecommunications Cable Splicing. Cengage Learning. ISBN9780827380660.
4. ^ ^abcdeAmerican Telephone And Telegraph Company (February 1959). Even PIC Cables(PDF). Bell System Practices – Outside Plant Construction and Maintenance, Section G50.607.3 Issue 2.
5. ^Color for Fiber Optic Cables
6. ^Abruzzino, James: Communications Cabling (2E), page 187. CNC Press, 2000
7. ^

RS232 serial cable layout

Almost nothing in computer interfacing is more confusing than selecting the right RS232 serial cable. These pages are intended to provide information about the most common serial RS232 cables in normal computer use, or in more common language 'How do I connect devices and computers using RS232?'

RS232 serial connector pin assignment

The RS232 connector was originally developed to use 25 pins. In this DB25 connector pinout provisions were made for a secondary serial RS232 communication channel. In practice, only one serial communication channel with accompanying handshaking is present. Only very few computers have been manufactured where both serial RS232 channels are implemented. Examples of this are the Sun SparcStation 10 and 20 models and the Dec Alpha Multia. Also on a number of Telebit modem models the secondary channel is present. It can be used to query the modem status while the modem is on-line and busy communicating. On personal computers, the smaller DB9 version is more commonly used today. The diagrams show the signals common to both connector types in black. The defined pins only present on the larger connector are shown in red. Note, that the protective ground is assigned to a pin at the large connector where the connector outside is used for that purpose with the DB9 connector version.

The pinout is also shown for the DEC modified modular jack. This type of connector has been used on systems built by Digital Equipment Corporation; in the early days one of the leaders in the mainframe world. Gasosta game download full. Although this serial interface is differential (the receive and transmit have their own floating ground level which is not the case with regular RS232) it is possible to connect RS232 compatible devices with this interface because the voltage levels of the bit streams are in the same range. Where the definition of RS232 focused on the connection of DTE, data terminal equipment (computers, printers, etc.) with DCE, data communication equipment (modems), MMJ was primarily defined for the connection of two DTE's directly.

RS232 DB25 to DB9 converter

The original pinout for RS232 was developed for a 25 pins sub D connector. Since the introduction of the smaller serial port on the IBM-AT, 9 pins RS232 connectors are commonly used. In mixed applications, a 9 to 25 pins converter can be used to connect connectors of different sizes. As most of the computers are equipped with the DB9 serial port version, all wiring examples on this website will use that connector as a default. If you want to use the example with a DB25, simply replace the pin numbers of the connector according to the conversion table below.

RS232 serial loop-back test plugs

The following RS232 connectors can be used to test a serial port on your computer. The data and handshake lines have been linked. In this way all data will be sent back immediately. The PC controls its own handshaking. The first test plug can be used to check the function of the RS232 serial port with standard terminal software. The second version can be used to test the full functionality of the RS232 serial port with Norton Diagnostics or CheckIt.

Testing occurs in a few steps. Data is sent on the Tx line and the received information on the Rx input is then compared with the original data.

The signal level on the DTR and RTS lines is also controlled by the test software and the attached inputs are read back in the software to see if these signal levels are properly returned. The second RS232 test plug has the advantage that the ring-indicator RI input line can also be tested. This input is used by modems to signal an incoming call to the attached computer.

RS232 null modem cables

The easiest way to connect two PC's is using an RS232 null modem cable. The only problem is the large variety of RS232 null modem cables available. For simple connections, a three line RS232 cable connecting the signal ground and receive and transmit lines is sufficient. Depending of the software used, some sort of handshaking may however be necessary. Use the RS232 null modem selection table to find the right null modem cable for each purpose. For a Windows 95/98/ME Direct Cable Connection, the RS232 null modem cable with loop back handshaking is a good choice.

Solrnet example. RS232 null modem cables with handshaking can be defined in numerous ways, with loop-back handshaking to each PC, or complete handshaking between the two systems. The most common null modem cable types are shown here.

Db25 Pinout Color Code

Db25 Pinout Colors

Rs232 Db25 Pinout