RS-232 is the electrical standard used on most serial ports.

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39 views

Arduino: RS232 Level Shifter or RS2323 Breakout needed?

I am trying to establish communications between an Arduino Mega2560 (Master) and a customised controller (Slave) via a Master-Slave RS232 link using Modbus RTU. The communication should be ...
0
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0answers
33 views

RS485 half duplex communication issue

I have a London MR400s taximeter and I wanted to communicate with it so I have connected it with my PC using RS485 half duplex cable. I am using termite terminal for polling and receiving the data. ...
0
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1answer
48 views

Current loop Converter

Is it possible to convert a 2 wires current loop to RS232, and from RS232 to current loop, I am trying to put an RS232 sniffer in the middle so I can see what they are communicating to each other. I ...
0
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1answer
49 views

Connection problem with RS485 system on PC with RS232 port

I am developing a system in which I have to integrate hardware. I am from computer background, so I don't have much knowledge about hardware systems. The issue is I have to integrate with London ...
-1
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0answers
89 views

Which type of bus to choose for 36 devices on one bus? [closed]

I'm a programmer and I just work with ARM SDK boards, but now I have a circuit design problem, so I hope you could help and correct me. First of all, I need the cheapest solution for designing a bus ...
1
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1answer
58 views

VHDL USB UART Problem

I've just described an UART transmitter and receiver in VHDL. In simulation everything seems to be fine. In FPGA, the loopback interface works well: I push a button, the transmitter sends data, the ...
0
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1answer
44 views

Digital Multimeter to RS232 Serial Port or USB - DT830D

I am new to Electronics and doing a hobby project. I want to take some readings and get them on the computer/laptop. I am ok with both RS232 (Serial) or USB (preferred). I have a DT830D Multimeter. I ...
7
votes
2answers
707 views

How does the MAX232 double the voltage?

MAX232 Datasheet Hi, I am currently a student so bear with me please! I'm currently using a powering the MAX232 with 5V DC, and when I measure from VCC to lets say, pin 3, I am getting a voltage ...
0
votes
1answer
59 views

What are all of the pins of the Beaglebone Black Rev. C serial (debug) header?

The Beaglebone Black Rev. C has a serial debug header with 6 pins. I would like to know what each of these pins is. If numbered 1-6 starting closer to the 5v barrel connector, pin 1 is ground, pin 4 ...
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0answers
56 views

Finding out RS232 commands from massage chair

Hey all I have a very quick question to ask about the Bus Pirate before I go ahead and order or not order it. I am looking to get the RS232 commands from a massage chair. It has an ugly, bulky "box" ...
1
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0answers
56 views

Remote control of audio equipment over RS-232 with Arduino

These questions are following on from my previous question Reverse engineering old serial devices and cloning with Arduino about the monitoring of RS-232 traffic. I had some good success and now have ...
2
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0answers
52 views

How to setup a RS-232 Cape for BeagleBone Black

I'm trying to use a RS-232 cape in a python script. A TU-S9 USB-to-Serial converter works just fine with same code I just change the port. So I don't think it is my code. The only thing I can think of ...
3
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2answers
156 views

Reverse engineering old serial devices and cloning with Arduino

I have a piece of music equipment that uses a remote control. This remote control communicates bi-directionally with the main unit. It communicates over RS-422 protocol (mainly for the cable distance, ...
0
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2answers
79 views

Convert FTDI USB signal back to serial

I have a data logger with a USB output (FTDI FT232RL) and I'm trying to get the information remotely using a XBee modem, but my problem is that I need to "convert" the USB signal back to serial to ...
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1answer
65 views

No correct signal from ATMEGA162 UART

I got the following circuit: simulate this circuit – Schematic created using CircuitLab And this code to run it: ...
0
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2answers
80 views

If RS-232 defines electrical characteristics, what is the transfer protocol?

From this answer, it says RS-232 defines the voltage levels and what not of a signal. I want to be able to read barcodes on my microcontroller with something like this. The closest datasheet I ...
4
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2answers
199 views

Opto-coupled RS-232 receive circuit

I am looking into a implementing a low-cost RS-232/422 opto-coupled receive circuit. The aim is surge protection and tolerance to DC offsets. The challenge is that the inputs should be completely ...
0
votes
1answer
68 views

Does BAFO “BF-810 USB to Serial Adapter (DB9)” supports full serial port?

Does BAFO BF-810 USB to Serial Adapter (DB9) support full serial port (hardware flow control) functionality? If not, how can I test full serial port functionality using serial port only with TX, RX?
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2answers
94 views

Pictures of different adapters, trying to understand how they work (PLC to PC communication)

I purchased the blue adapter in the picture as a USB/RS232 converter. It takes in the RJ12 cable from my PLC, and converts it to a USB input. Now when I try to use an RJ12-DB9 Female and then connect ...
0
votes
1answer
94 views

Is an USB-to-UART converter different from an USB-to-RS232 converter? [duplicate]

I have a USB-to-RS232 converter. The GND, TX and Rx pins of the RS232 I connect to GND, Rx and Tx on a development board I have. I've set the right baud rate, flow control and other settings in my ...
0
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0answers
118 views

MAX3232 overheating/burnt after connecting to PC

I've got a MAX3232 Serial-to-TTL RS232 board which I am currently using in factory assembly lines. I don't have its picture, but here's a similar product: This is the circuit I've managed to figure ...
5
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5answers
2k views

Why are there so many resistors in a typical schematic?

I know that some resistors cause pull-up or pull-down or work as a voltage divider and/or current divider. But sometimes I cannot understand their function in some simple circuits: Take this motor ...
1
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2answers
65 views

Simple FPGA serial communication not working

FPGA board (manual) USB-to-RS232 cable (controller) synthesis reports I created a simple schematic which shorts the TXD and RXD pins according to the manual. However, when I use RealTerm to send ...
0
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0answers
154 views

Send AT commands to UART device, what am I missing?

It all started with me wanting to change the pairing code of a bluetooth device, and now I'm knee-deep in electronics... I have a miniELM327 bluetooth interface with PIN "1234" , I want to change it. ...
3
votes
2answers
595 views

Can I split one RS232 output signal into two signals? [duplicate]

I have one controller which processes data from a weigh scale. With it I can capture data using hyper terminal on a PC (RS232 communication - standard DB9 connector). Now I want to analyze it on ...
0
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2answers
87 views

MCU cannot communicate with Bluegiga WT12 module

I have the evaluation kit EK-WT12 for Bluegiga WT12 module being controlled by a TI Launchpad. I have used the evaluation kit to communicate to a computer with SPP profile and I have sent and received ...
0
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0answers
78 views

USB CDC RS-232 interface to Bluetooth or WiFi

I have a device that communicates with a computer via an USB CDC RS-232 interface. The thing is that I want to build an interface (on top of that USB interface) that enables the device to ...
1
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3answers
211 views

Can you safely “short circuit” 2 signals when they compete for the same pin to avoid having to use a multiplexer?

I'm developing for a very limited, 8 pin LPC810 microcontroller and have to connect multiple signals on a single pin. Obviously, if there's only 1 output signal on a bus, that should be OK, but what ...
0
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0answers
209 views

UART RS232 Converter via MAX232 malfunctioning?

I am a newbie, trying to test Launchpad Tiva's UART channels. I have set up the circuit in order to connect my Launchpad's UART to RS232 port of my PC. However I have the following problems, which I ...
1
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1answer
125 views

USB to Serial cable and VCC current output [closed]

I have question about generic USB TTL Serial cables, FTDI FT232R-based. The cables differ in voltage, 5V, 3.3V and output current. USB TTL Serial Cables I need a cable for a USB to serial ...
5
votes
2answers
94 views

FPGA able to send data, but unable to receive data. (UART - RS232)

I have a DE0-nano FPGA board and I am trying to establish a serial connection with my PC. I am using the RS232 implementation from here: http://www.fpga4fun.com/SerialInterface.html I have tested ...
3
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2answers
84 views

Serial comms over 3m cable, shared with USB

I am designing a system that needs to do serial comms over a standard USB cable, as well as normal USB (but not at the same time). In other words, when plugged in to a PC it will appear as a USB ...
0
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1answer
106 views

Connecting to pins on USB to Serial module (contains FT232RL chip)

I have this module: My question pertains specifically to the RX and TX pins shown (sorry for having it upside down, only way I could make it look clear.) I don't understand why there are 4 pins, ...
18
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3answers
5k views

Difference between UART and RS232?

Most of the time RS232 and UART come together in serial communication theories. Are they both the same? From my readings I concluded UART is a hardware form of RS232 protocol. Am I correct?
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2answers
246 views

Connect DHT22 to serial connection

I'm trying to find a way to connect a temperature and humidity sensor DHT22 to an XBee's RX/TX pins without an additional microcontroller(Arduino or anything that needs software) or reprogramming the ...
1
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2answers
109 views

How can I know whether a random “known not TTL” RS232 device will work with any old random USB-RS232 converter?

I've been hunting around for RS232 converters for a little while now, trying to get my head around the way RS232 works (or at least how it's supposed to), and the way RS232-USB converters (more ...
0
votes
1answer
405 views

How do the TX/RX/CTS/RTS/DSR/DTR/DCD/RI/GND signal monitor LEDs on these odd FTDI-based USB-RS232 converters work?

While searching for a "decent" USB-RS232 converter, I turned up the following two fascinating creations which have status LEDs for all the signal lines: This concept really appeals to me from a ...
0
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2answers
72 views

Do you really need all of the sigals for a general RS-232 port?

I know that having TX, RX, GND, RTS, CTS are good. What about all of the others? Do devices these days even make use of the other pins (DSR, RI, DCD, DTR)? Is it safe to generally leave out these ...
2
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0answers
118 views

pic24fj128ga310 uart not working in application, but works with PuTTY

I'm trying to connect a PIC24FJ128GA310 mounted on an Explorer 16 board with an embedded wireless module. I have been able to set up both to communicate perfectly well with PuTTY (an equivalent to ...
1
vote
2answers
239 views

Speed problems in homemade RS232-to-TTL converter board

I'm still trying to debug this RS232-to-TTL converter board that I've made, shown below. Now I think I've narrowed down the problem to speed: it works fine at 57,600 baud; but it inserts some ...
2
votes
1answer
106 views

Is it possible to use the RTS pin as DTR?

I'm deveoloping a project with a raspberry Pi that involves serial communication. In order to properly handle voltage levels, I used a max3232 converter between the raspberry and the external device ...
5
votes
2answers
962 views

Problems with homemade RS232-to-TTL converter board based on TI's MAX232

I've designed an RS232-to-TTL converter board based on TI's MAX232 IC that I plan to use to program a few custom Arduino boards that I have. However, I'm having trouble with the board and I'm hoping ...
0
votes
0answers
63 views

Why can't I use my AVR programmer with serial functions?

I recently created a project in which I made my own AVR test bed based on the Arduino Uno. I used the ATmega 328P and I have set up all the fuses for the external clock and the Arduino IDE to ...
0
votes
2answers
164 views

3.7v > 3.3v voltage stepdown with logic-driven on/off control [paused]

(PAUSED): This topic is currently on hold as I source necessary hardware. I need to connect a Wi-Fi/RS232 module to a low-powered monitoring device, and for maximum portability, I'd like to power the ...
1
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1answer
212 views

Voltage level too low for MAX232

I'm trying to connect TI's MAX232 to my Arduino so that I can communicate with my PC. I have connected it exactly as the picture shows: Tx/Rx are not connected because I just wanted to see if I can ...
3
votes
3answers
384 views

Can I screw up my board by guessing which RS232 pins are which?

I have a Raspberry Pi that I want to hook up to a serial (RS232) cable. I've found and read some information about this, so I know what pins on my RPi are Rx/Tx/3.3V/Gnd... Now the cable I'm hooking ...
0
votes
1answer
127 views

Connecting 4 devices on RS232

I have two PCs (very old, without usb but rs232 port) that talks via RS232. They send to each other very small bit of info ( one character every 10sec). Now I need to connect additionally two sensors ...
1
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0answers
118 views

RS232 Grounding question

I want to connect 2 devices together using RS232. I initially thought both devices used the power ground as the reference signal for their RS232 (they're powered by the same PSU) so I designed my ...
2
votes
3answers
248 views

When do we use all pins in RS-232 cable?

I think the minimum for simplex communication are TX so we can transmit and the power supply pins +Vcc and GND. That is all we need. When do we need to use all 9 pins of RS-232? I think that the ...
1
vote
2answers
414 views

How would I make an Arduino Due recieve RS-232/422 signals?

Background on this question is here: Oops, I accidentally need to build an embedded system. What would that look like? I'm looking at purchasing an Arduino Due to take in 3 (well, ultimately 5, but ...