Questions tagged [communication]

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

7
votes
3answers
9k views

Long range (~15 km) low baud-rate wireless communication in a mountain environment (no LOS)

I'm trying to implement a point-to-point communication system in a mountainous environment where the base station and the client are at least 15 km apart, without any line of sight (LOS). The ...
17
votes
5answers
59k views

Difference between Hz and bps

Does Hz and bps mean same? Can a signal be transferred at rate of say Mbps on a channel bandwidth of few Khz?
77
votes
3answers
125k views

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?
22
votes
6answers
8k views

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 <...
50
votes
2answers
20k views

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?
22
votes
11answers
25k views

Injecting a communication signal over DC power supply lines

I'd like to be able to daisy chain multiple devices using just the power supply wires and then inject a communications signal over the power lines to turn it into a half duplex network. Are there any ...
161
votes
4answers
217k views

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, ...
184
votes
8answers
31k views

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 ...
6
votes
4answers
1k views

Can Cellphones be used for Ad Hoc Communication?

Can Cell Phones be (legally) used Adhoc, (ie, Point-to-Point) Communication? For example, let's say I'm in a remote area of the woods, or a valley. Can I configure cell phones to be used as true ...
39
votes
2answers
12k views

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]. ...
13
votes
3answers
22k views

UART receiver clock speed

I was trying to understand UART fundamentals.It is understood that It is an asynchronous communication protocol and hence the TX and RX clocks are independent of each other The data reception is ...
12
votes
8answers
23k views

Wireless communication over long distances

Would like to communicate between an Arduino and a PC but over a distance of 2500+ feet outside in the open, wirelessly. What would be the best way of doing this? The communcation devices I have ...
1
vote
1answer
581 views

Shallow underwater wireless sensor network

I need to make shallow (max 2m) underwater wireless sensor network. Data payload is about 10kB/s. I know that VLF band (~3-30kHz)could be the best solutions for that, but cause of time-to-market I ...
0
votes
3answers
787 views

Suggestions for a Point-to-Point reliable Wireless Communication Module

I've to implement a wireless communication system. Details are as follows. Range is about 600m Point-to-point communication No LoS is available. (but not highly obstructed) Won't need much higher ...
0
votes
1answer
979 views

Time limited and band limited signal

How can a time limited signal be of infinite bandwidth and a finite bandwidth signal be of infinite duration?
33
votes
13answers
16k views

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 ...
9
votes
6answers
10k views

Good RS232-based Protocols for Embedded to Computer Communication

I'm working on a project that involves a good bit of data communication between a remote Arduino and a computer. The wireless connection is through a pair of XBees, so we have a RS232 link between the ...
18
votes
8answers
60k views

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 ...
8
votes
3answers
43k views

Starting with I2C on PIC18s

For a project I'd like three PICs (two slaves PIC18F4620, one master PIC18F46K22) to communicate over the I2C bus. Later on, more slaves may be added (like EEPROM, SRAM, ...). I'm writing the code for ...
6
votes
2answers
11k views

Power line communication principles

What are the principles of implementing Ethernet over power lines ? Is it reasonable/possible to create an Arduino shield which will provide both power & network ? (properly isolate the "dangerous ...
3
votes
2answers
837 views

Bandwidth for a single tone

If I am using a channel only for morse code (CW), with one frequency and interruptions for dots and dashes, is the necessary bandwidth of the channel twice the audio frequency of the tone used for CW?
2
votes
1answer
277 views

Selecting a transceiver module for a wireless communication system [duplicate]

Possible Duplicate: Suggestions for a Point-to-Point reliable Wireless Communication Module I got a project to design a wireless communication system in order to communicate between the factory ...
1
vote
1answer
495 views

I2C on FFC or IDE cable - interference?

This is a follow-up question on this answer. I need to communicate with I2C over approximately 10cm and I'd like to use an FFC or IDE cable for that. Earlier, I used an FFC cable to link a segment ...
0
votes
1answer
224 views

WPC Communication (Modulation)

I have found this image and wonder how to calculate or determine "Cm", because I like to simulate this circuit in LTSpice. Also should I use a Mosfet or a voltage controlled switch? Can someone help ...
-2
votes
2answers
209 views

Can a smartphone send directly a message to another smartphone 20 miles away? [duplicate]

According to this website, a typical cellphone has enough power to reach a cell tower up to 45 miles away So, can a smartphone send directly a message to another smartphone 20 miles away?
19
votes
8answers
33k views

Communication between multiple microcontrollers

I'd like to start implementing a system consisting of N microcontrollers (N >= 2 MCUs), but I would like to know the possibilities to let them communicate one with the other. Ideally, (N-1) ...
8
votes
3answers
9k views

Using a LED to transmit data

I am curious about the possibilities offered by LEDs to transmit data over a short range (2 or 3 meters), and what maximum data transmission rate can be expected from carefully chosen, but consumer-...
17
votes
3answers
29k views

What's the maximum CAN bus frame (message) rate at 125 kbit/s?

My CAN bus is running at 125 kbit/s and is using extended frame format exclusively. I would like to know what's the maximum rate of CAN frame I can send out. Suppose the data length is always ...
12
votes
4answers
7k views

Implementing a CAN protocol layer in software

Background I'm developing a project which will require the modest microcontroller specs of: 8 12-bit, 10kHz ADCs 1kB of RAM 48-QFN or smaller footprint 20kbps daisy-chainable noise-resistant and ...
15
votes
3answers
4k views

How can over 24 GHz communication be possible?

I read the article Google wants the US' wireless spectrum for balloon-based Internet. It says to use over 24 GHz frequency spectrum for communication. Is it ever possible to generate that high ...
14
votes
7answers
30k views

Hyper terminal equivalent in windows 8 [closed]

I need to do some communication between 8051 micro-controller and PC . There used to be a hyper terminal for this purpose in windows XP. I m using windows 8 now. So can anyone suggest me some ...
2
votes
4answers
16k views

Sending data using 4 pin 3.5mm jack into smartphone

I have been looking around for some time and haven't found helpful information on how this is done. I am working on a project that intends to send data through the headphone jack to be processed by a ...
21
votes
5answers
8k views

Why do people use AT commands in serial communication?

I need to know why people in embedded systems use AT commands? When I have asked people say that it is a standard. So my question is: What does "AT" means? Why do people keep saying it's a standard?
17
votes
2answers
13k views

transmitting 5v signal over a long cable

I'm seeking for help here as I need a reliable answer to this. I need to get an input signal (low frequency 5v digital pulse), to a micro-controller from a (...
2
votes
6answers
4k views

Low cost simple communication between two microcontrollers

What tradeoffs and connection options are there in low cost bidirectional communication between just two microcontrollers? In this case: Master/Slave relationship, bidirectional data flow Distance ...
15
votes
4answers
30k views

Why the conversion to Intermediate Frequency?

While studying about various communication systems (Superheterodyne receivers and Television receivers, to name a few) I often come across blocks that convert RF signals to Intermediate Frequency (IF) ...
8
votes
9answers
3k views

What are the ways I can make my circuit communicate with a computer?

I am a novice at electronics hacking. I would like to know how I can make a circuit communicate with a PC. Take for example, a simple circuit, with one LED and a switch. The switch on the circuit ...
4
votes
3answers
1k views

FM Quadrature detector - is it the best choice

My input is an FM carrier of 80.00MHz. It is FM modulated with 625kbpsec data. The deviation from carrier is about +/-700kHz. The data never spends more than about 38us in a low state or high state i....
8
votes
3answers
900 views

Rather complicated sensor network

I was working on a project recently and it was the first one which was involved enough to make the sensor networking complicated. In the end, I think the communication was the bottleneck in terms of ...
4
votes
4answers
2k views

How does sender and receiver clock time periods synchronize in data communication?

In asynchronous data communication, Initiation of data communication between two stations(sender and receiver) involves synchronizing their clocks to ensure both stations are agreed upon same bit ...
2
votes
1answer
7k views

Frame size range calculation for stop-and-wait protocol

I have a question and answer below. The answer seems to show less working on how it derived. My question is if the efficiency of at least is changed to say 60%? Will it still be the same answer? ...
1
vote
2answers
2k views

GSM/GPRS AT command - hitting a link

I am trying to target a specific page (script) on my webserver using a GPRS modem. I can hit my domain, and get a reply back but then when I am trying to call my script it just won't let me: ...
0
votes
3answers
4k views

Operation of LC circuit in Frequency Modulation with simulation and linking it to the basic principle of frequency modulation [duplicate]

Can somebody help how message signal (words spoken near microphone) is modulated using LC circuit and how lc circuit oscillates at particular frequency by applying dc voltage. In the below circuit l1 ...
15
votes
3answers
323 views

Communication among briefcase halves

I'm building a small laptop-ish device in a briefcase. Imagine the green wires aren't there. The LCD half lies somewhat deeper in its case than the keyboard part. For now, testing and programming, I'...
5
votes
5answers
5k views

Implement send-only (one-way) Ethernet cable

I want to build a unidirectional comminucation. In transportation layer of this device, it needs a one-way media to send data from side A to side B. All commercial products use SFP. I tested some SFP ...
4
votes
3answers
2k views

High Altitude Balloon Communication

Our team is planning to make a HAB (High Altitude Ballon) project for our university. We are planning to use XBee pro 868 RF modules (we are in Europe so we can not use 900 MHz band). We have to ...
4
votes
3answers
2k views

Communicating via USART with an AVR - Input Buffer?

I am currently building a robot (as some of you may know from my previous questions). The current task I a dealing with is that of communication. To keep things simple, assume I have 5 commands to ...
3
votes
3answers
645 views

Doubts on Implementing a Simple Protocol for XBee Comms

A system that I'm developing will use XBee modules for a point to point connection between a micro-controller and a PC. Data will only be sent only in one direction -Micro to PC and at 10-20fps. The ...
3
votes
2answers
729 views

Is it OK to have data lines and AC in the same multicore cable?

I need to provide the following over sections of 1m multicore cable, totaling around 15m. 240v AC 5v DC GND RX TX Will the AC cause problems for the Serial data?
3
votes
3answers
2k views

Data over power line in a car

I am trying to build a communications system for a car, for turning gadgets on or off. One idea was to parasite on power lines, but what kind of components and signaling could be used for this? I am ...