Questions tagged [twisted-pair]

Most commonly a type of transmission line that consists of two individual wires twisted together. Its differential nature attenuates common-mode interference present in the environment, which is useful in the transfer of differential signals (even low-frequency ones). It is commonly used for differential digital communication protocols such as ethernet.

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RS232 and RS485 sharing same wires

I'm planning a serial port that can either work as RS485 (half duplex mode) or as RS232 (configurable by the user). There are several UART to RS232/485 chips around (like LTC2873), where a GPIO ...
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Can I use thicker wires or twisted pair for Ethernet?

I'm planning to use 2 types of connectors: A : GND + 24V + 100Mbps ethernet (4 wires) + 2 wires with various functions B : 1 Gbps ethernet with PoE (8 wires) For type B, I found of the shelf ...
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Twisted pair wiring 4-20 mA sensor

I have a pressure sensor with 24 V, GND and 4-20 mA signal output pins. It will communicate with a PLC. I will only use 3m of wire max. for each pin. The installation will be on the rooftop maybe a ...
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Will twisted pairs aid/hinder or be superfluous?

I am making up two looms, each with four cables of 1.2 mm CSA cable. The cables are to activate four 24 V solenoids. Cable runs approx. 4 meters. The two off cables will connect to two off bulk-...
paul's user avatar
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Twisted Triad vs. Twisted Pair for RS-485

I'm looking for information regarding twisted triad vs twisted pair cable use with RS-485, especially in applications with long distances outdoors. With twisted pair like Belden 3105DB, the drain is ...
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Shielded -vs- Non-Shielded, running CAN Data Cable w/ 115/200VAC 3-Phase @ 400Hz

*Edited, AGAIN, in an attempt to remove any confusion Settle this debate! I am designing a Harness for testing the functionality of a PDU (Power Drive Unit), operated using CAN (ARINC-825). Prior to ...
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CAN physical layer flexibility

I'm considering designing a CAN bus (CANopen) where part of the bus, closest to each node, does not use twisted pair. Partially the bus will run in a DSUB, but partially through stackable header or ...
NoobPointerException's user avatar
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Twisting four CANBUS wires (High, Low, GND, PWR)

From what I understand, the High/Low CAN wires must be a twisted pair and it seems like a bad idea to create a 3-wire braid with the High/Low along with the GND wire, let alone with PWR. Just to be ...
John Smith's user avatar
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Length of wires after they are twisted?

I have looked all over and haven't seen any questions about this topic. This may be more of a mechanical question, but none the less, the dilemma on hand is how does twisting a set of equal length ...
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Twisted pairs incompatible with very slow ground-referenced signals?

I am stumped by the behavior of a cable assembly I have made out of a pair of repurposed ethernet cables, and am hoping you can help me rule out issues that may be caused by twisted pairs. I realize ...
Aaron Kimball's user avatar
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Current transformer wire issues

I would greatly appreciate some advice regarding twisted pair conductors for a current transformer. So, according to the manufacturer, whose equipment I am installing, I need to connect 10 AWG, ...
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Why do UTP pairs need different pitches?

Why do unshielded twisted pair cables need a different pitch/twist rate for every pair of wires in a cable? Most of my reading on UTP says that the pairs in a cable must have different pitch or else ...
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Twisting two cables: Does the rotation of each cable play any role?

When twisting two cables (imagine f.e. something like a twisted pair cable), does the rotation of both cables have any importance? I.e., is it important that each cable rotates around its own axis as ...
thz's user avatar
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Why are coaxial cables typically faster/longer than twisted pairs?

I'm having trouble understand why coaxial cables tend to have higher bandwidth compared to twisted pairs. I couldn't find any source explaining why, they just mention the fact. For instance: "In ...
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9 wires in a CAT5e cable?

I just cut open a CAT5e cable since I wanted it for a project which required several twisted shielded pair cables. To my surprise there were 9 wires with isolation? I was under the impression that ...
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Why don't oscilloscope probes use twisted pairs?

I was reading online about how Ethernet cables use twisted pairs instead of coaxial cables because it's better in some way. Some websites say that twisted pairs cost less, can carry higher frequencies,...
loadingnow's user avatar
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How best to allocate signal wires to 4 twisted pairs that best reduces inteference

I have to transmit digital signals 30meters including power. I am going to use a cat 6 ethernet cable with 4 twisted pairs (8 wires in total). I can already assure that my signal gets to the other end ...
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How can a cable tester verify correct shielding/twisting of wires?

Background: The company I work for makes a variety of special-purpose cable assemblies to go with equipment we make. The people who build these cables aren't doing a 100% reliable job, and nobody ...
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Can I use Ethernet UTP instead of COAX for satellite TV

I'm planning on having a satellite TV subscription installed on my home, when the satellite dish is installed they will need to run a coax cable from the satellite dish all the way to the decoder ...
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How does a twisted pair cable reduce inductive coupling compared to non twisted pair cable?

Can anyone explain this concept with figures for both non twisted pair cable and twisted pair cable?
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What is the difference between capacitative and inductive coupling in a twisted pair?

I'm learning about networking and there is this passage: "Twisting cancels out inductive coupling, while the shield eliminates capacitive coupling." What kind of effects are these, ...
username128437855's user avatar
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Why we don't use twisted cable in dc power?

I general applications, we don't see DC-Power lines as twisted pairs. Even in standard cables, only the data line pair is generally twisted. Do we assume that DC-power lines are not worth twisting? Or ...
Naval Kishore's user avatar
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How to identify a coax connector vs twisted pair connector

I need to have a connector that will bring in COAX input to my PCB. I have this Rosenberger HSD Connector Catalog. On page 33, "99S12D-40MA5-y" - is this connector a twisted pair connector ...
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Effects of twisted pair in 120V AC

In Square D's marketing copy for their plug on neutral load centers, they have a photo for demonstrating "cleaner wiring" in which the hot and neutral wires are twisted inside the panel ...
TBridges42's user avatar
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Would twisting 3 wires together be as effective (or close) to a twisted pair?

Would twisting 3 wires together like a twisted pair would be as effective as an ordinary twisted pair? Or at least a definite improvement to not twisting them at all? simulate this circuit – ...
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WS2812b data over 35m line

Single WS2812b LED are connected over 35 meters (115 feets) UTP Cat. 5e cable and it's not working as expected. Getting wrong colors. Another WS2812b placed in parallel (not chained) on board close to ...
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Four wire voltage sensing, all four wires in one cable?

If I twist the power positive and negative wire together and do the same for the sensing wires, can all four wires (two twisted pair) be in one cable or they should be physically separated from each ...
ElectronSurf's user avatar
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Can I improve serial data signal using reversed output on a twisted pair?

This is a serial data communication with one or several transmitters and one or several receivers. From the transmitter I have one serial data output (D+) and a second, reversed serial data output (D-...
Fredled's user avatar
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5 votes
3 answers
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PCB equivalent of wire twisting

I've a PCB with quite some electronics including a few motor drivers (30V, 100kHz PWM), and a few brushed DC motors 1 meter further away. These motors each have a quadrature encoder, so next to their ...
Huisman's user avatar
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Can twisted pair replaced by two wires which are closely placed?

If I have differential signal wires, can I place two wires closely 1mm-2mm gap between them but not twisted? (1mm or 2mm gap is fixed it won't change from place to place ) I am using Differential I2C ...
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Data + Power connector and cable suggestion

I need to decide about how to connect two custom designed electronic units. One is main (execution) unit, and the second is hand-controller unit. Those units have to be connected by wire. The ...
IgorEkis's user avatar
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Is there any benefit to using twisted pair for short-distance I2C?

I know twisted pairs are important for differential signals, which I2C is not. I also know I2C is not intended to be used over long wires. However, I made a design where I need to use a cable to ...
Arthur Tarasov's user avatar
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Terminating Resistors on Ethernet Port

I'm using Ethernet (CAT5/5e/6) cables to communicate with the PCA9615 Differential I2C buffer. These cables roughly have a characteristic impedance of 100 ohms, but I have a few questions about ...
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Swapping out RJ-45 connector on Differential I2C circuit

I'm trying to use Sparkfun's Differential I2C Breakout circuit into my own design, and I'm looking to replace the RJ-45 connector. It's too big (having a footprint size of 15.24 mm x 15.24 mm), and I ...
BestQualityVacuum's user avatar
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Twisted pair's effect on power supply rise time

I am having a tough time wrapping my head around this question. I am well aware of the benefits of using a twisted pair for signal wires: the cancellation of common mode noise coupled onto the wires, ...
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How does twisted pair turn rate affect interference rejection bandwidth?

I'm curious to know how the turn rate of a twisted pair affects the frequency of crosstalk interference rejection. It's clear that an untwisted pair has no inherent rejection. Alexander Graham Bell ...
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Impedance Control in Twisted Pairs and PCB

Why do differential signal traces on a PCB require a reference plane to have a controlled impedance? Whereas, in an unshielded twisted pair there is no reference, there are only the two conductors? ...
Swifty's user avatar
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Shielded Twisted Pair noise immunity

If I am correct in assuming a twisted pair cable is used to provide reduced susceptibility to noise. What is the benefit in having the cable twisted when it is inside a foil screen/shield? Would ...
Swifty's user avatar
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Twisted pair with shield and drain wire

Ive been posed with a problem regarding calculating the characteristic impedance of a shielded twisted pair with a drain wire. While I understand how to calculate this for a "normal" shielded twisted ...
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Questions about CAN

I'm trying to build a network of interactive LED matrices which will communicate to each other. Each node will be a circular PCB containing an 8x8 RGB LED matrix that is connected through a vertical ...
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Running STP and high-current AC cables together

I am about to install a backup generator about 40m away from my house. There is no question what cables to run for the AC current (which will be 230V 50Hz up to 30A) — doubled 10AWG (6mm2) to keep ...
Greendrake's user avatar
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Structure of Pairs inside a Cat Cable

Is there a standard arrangement for the pairs inside a Cat7|6|5 Ethernet Cable? As shown in the picture, they are in the sequence Orange-Green-Brown-Blue, or the Orange Brown always as opposite pairs,...
Brethlosze's user avatar
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2 votes
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Ethernet connection using only one twisted pair

For my degree work, i make some reseaches for different bus systems and i've found ethernet a bit different than others: The old 10Base5 and 10Base2 ethernet used only one pair of conductor to ...
Dankó Dávid's user avatar
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3 wire signal to 4 core shielded twisted pair

So I have some flow sensors, which have a 3 wire interface. The three wires are 5V, signal, and ground. Signal is pulse output that varies between 5V and ground at a maximum frequency of about 200 Hz....
rcsandell's user avatar
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The CAN bus in this vehicle has only one 120 ohm termination resistance. What problems would this provoke?

This vehicle that I've started co-developing is designed with only a 120 termination resistor on the CAN bus. Obviously there should be two of those resistors on two ends of the bus. I will be making ...
Bart's user avatar
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Shielded twisted pair balanced transmission line implementation

I want to send a signal from board 1 to 2 through 20 cm line. I have four channel in differential, First I add them, can I send them through shielded twisted pair like this: Do I need a buffer? why? ...
mohammadsdtmnd's user avatar
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Power over ethernet and common-mode termination

I have a non-standard Power over Ethernet application (connector, and devices are not ethernet standard but we are using ethernet pairs and protocol for communications). On looking at PoE schematics I ...
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Using optocouplers at the end of a twisted pair

I am designing a dumb "isolation box" that is to sit between a computer and medical data acquisition equipment. The purpose of this box is to inject power and to provide communications and digital ...
Edgar Brown's user avatar
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CAT5 for telephony

I wish to extend my incoming telephone connection using CAT5 as I've heard it could provide better performance than standard single stranded telephone wire over long distances. There are only two ...
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Locating pairs on an LVDS cable

For a 2-row connector intended to interface a cable to a PCB, which method is preferable for twisted pair LVDS signals? Horizontal Pairs: LVDS1-    LVDS1+    ...
pr871's user avatar
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