Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [communication]

Exchange of information between devices. Communication can be wired or wireless.

The "communication" tag is very general. In many cases, it's better to tag a question with a more specific tag, such as (for example) , , , , , , , , , , , , , , , , , , , , , , , , , , , , or etc.

1359 questions
202
votes
4 answers

USART, UART, RS232, USB, SPI, I2C, TTL, etc. what are all of these and how do they relate to each other?

As a novice electronics hobbyist, I have heard these terms and more being thrown around everywhere. At its root, I understand that they are all based on communication between devices, computers, peripherals, etc. I have a basic understanding of how…
capcom
  • 5,882
  • 14
  • 48
  • 59
198
votes
8 answers

Why does USB have 4 lines instead of 3?

USB specifies 4 pins: 1. VBUS +5V 2. D- Data- 3. D+ Data+ 4. GND Ground Why is this not 3? Could the Data and Power not share a common ground? Am I correct in understanding that D- is the ground for D+?
Mark Harrison
  • 10,419
  • 27
  • 68
  • 95
121
votes
5 answers

Difference between UART and RS-232?

Most of the time RS-232 and UART come together in serial communication theories. Are they both the same? From my readings I concluded UART is a hardware form of the RS-232 protocol. Am I correct?
tollin jose
  • 3,092
  • 9
  • 35
  • 53
64
votes
3 answers

How does my screen driver handle so much data?

I just did some quick calculations: On my MacBook I have a resolution of 2560x1440 multiplied by 24 Bit for colors we get 11.05MB for a single picture or 663MB per second at 60 fps. I guess there is some compression, but for example when I move with…
Felix Crazzolara
  • 698
  • 5
  • 14
59
votes
2 answers

In a USB cable, is it OK to swap the D+ and D- wires?

I heard that D+ and D- are differential signals, does it matter if I swap them when connecting a USB device to the computer?
Yan King Yin
  • 701
  • 1
  • 5
  • 6
53
votes
2 answers

Why are USB devices slower than 480 MBit/s

Motivation With a signaling rate of 480 MBit/s USB 2.0 devices should be able to transmit data with up to 60 MB/s. However today's devices seem to be limited to 30-42 MB/s while reading [Wiki:USB]. That is a 30 percent overhead. USB 2.0 has been a…
Chris
  • 671
  • 1
  • 6
  • 7
47
votes
7 answers

Why aren't headphone jack shaped plugs used for data?

With Apple's lightning cable, and USB 3.0, reversible cables are taking off, and I personally think this is very convenient. But we have had better than reversible for a long time, in the form of the headphone jack, which can be inserted in any…
Drew
  • 713
  • 1
  • 6
  • 8
38
votes
13 answers

Software to create timing diagrams

In my professional life, I sometimes need to create timing diagrams for protocols: UART, SPI, etc. However, I can't find any good programs available. What programs can be recommended for this and what is the experience using them?
Seidleroni
  • 1,674
  • 2
  • 14
  • 19
30
votes
2 answers

How can the GPS position update rate be 10 Hz?

Based on stuff on the web (Wikipedia and others) the GPS navigation message bit rate is 50 bit/s. That includes all data needed for user position calculation (time, ephemeris, almanac, etc.) It seems that the packet from a satellite should be much…
Alihaji
  • 446
  • 4
  • 7
30
votes
6 answers

Serial protocol delimiting/synchronization techniques

As asynchronous serial communication is widely spread among electronic devices even nowadays, I believe many of us have encountered such a question from time to time. Consider an electronic device D and a computer PC connected with serial line…
Eugene Sh.
  • 9,986
  • 2
  • 26
  • 41
29
votes
8 answers

Can I use I2C over 2m cables?

In my current project, I need to communicate between a microcontroller and some sensors over I2C. One of them is a temperature sensor, it needs to be placed at approximatively 2 meters far from the microcontroller. I cannot choose another protocol…
JackOfHearts
  • 649
  • 1
  • 6
  • 14
29
votes
8 answers

When should one switch from ASCII to advanced serial protocols?

All my microcontroller devices that communicate with the PC via UART use ASCII strings for sending commands and receiving data (as implemented in Arduino). That's what I learned when I began digging into electronics and I always found sending bare…
I have no idea what I'm doing
  • 1,361
  • 2
  • 16
  • 25
26
votes
8 answers

Is CAT5 cable good enough for RS-485 vs "true" RS-485 cable

I have a serial comms project coming up. A number of boards with RS-485 interfaces need to communicate. Date rate is 57600bps and cable length will be less than a few hundred feet. Will shielded CAT5 cable work well enough in this situation or…
SeanLabs
  • 485
  • 2
  • 6
  • 11
26
votes
8 answers

Is it possible to receive information if the received power is below the noise floor?

This relates to my previous question, which I think I have asked in the wrong way: How to insert background EM noise into pathloss equation? I wasn't really interested in detectability of the signal, and I have phrased that question very…
David K.
  • 423
  • 4
  • 11
26
votes
3 answers

How is 255 Tbit/s processed in optical fiber communication?

I have never understood how the new record breaking data transfer speeds are achieved in terms of converting from/to electrical and optical signals. Suppose we have 255 Tbits of data and we want to transfer it in one second. (This is a real world…
stevie
  • 469
  • 5
  • 10
1
2 3
…
90 91