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

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AVR - Simple(st) serial port programmer

As I'm just getting started with learning anything about microcontrollers, I started from making a very, very simple LPT port programmer (...I think it was just about 4 resistors). It worked well with ...
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3answers
71 views

Simple RS232 to 8 bit Parallel circuit

I want to make a simple rs232 to parallel (8 bit) converter. I would like the input to 1 wire and the output can just be 8 bit with no strobes etc. and run at high speeds (ideally up to 1Mbps, put ...
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1answer
37 views

Wiring RS485/422 to RS232 converter to a given device pins [closed]

I'm trying to establish a full-duplex and then a half duplex communication and need to wire a device output to an RS485/422 to RS232 converter. Here is the device output pins for full and half ...
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1answer
27 views

Accessing RS232 Rx Tx instead of OTG on stellaris LM4F232H5QD evaluation board

I am asking two related questions here: I can see a program uart_echo for stellaris lm4f232h5qd . What I want is that I need to access this data on teraterminal using PA1 and PA2 pins instead of ...
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1answer
65 views

VHDL RS-232 Receiver

I have been trying to design an RS-232 receiver taking an FSM approach. I will admit that I do not have a very well-rounded understanding of VHDL, so I have been working on the code on the fly and ...
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1answer
59 views

Pin assignment on rj45 when using rs232

I am having a problem creating a cable to connect with two devices. The first devisce is an Intellivue MP70 that I want to connect to the RS232 port using an RJ45 end. On the other side there should ...
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1answer
199 views

Connecting GSM SIM900A module with Ardunio

I have bought an SIM900A Mini V4 GSM module. Here is the module, I want to configure with arduino to send and receive SMS. Do I have to connect TXD of this module--Tx of Arduino & RXD of this ...
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1answer
56 views

RS232 Splitter Capable of Transmitting/Receiving data to one device and only Transmitting to another

I was wondering if it is possible to have a RS232 splitter that is able to split the data into two RS232 connections, and allow for one of the connects to still be able to transmit data back through ...
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0answers
56 views

Can a USB 5v 0.5A powered pcb sent data to a 3,5 mm jack using a 2nd usb port via usb-to-3,5mm converter wire?

I am designing a MCU for a device that is powered by USB. This device needs to send simple serial commands to an 3.5mm stereo port on a monitor. The wanted to use USB-to-3.5mm jack converter wire, ...
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2answers
100 views

How can RS232 DTR / RTS pins be used for Power?

I want to interface to this device where (sec 4.2) states can be powered from the DTR and RTS handshaking lines by having one high and one low Also, Wikipedia states: No method is ...
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2answers
68 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 ...
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0answers
50 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. ...
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1answer
71 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 ...
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1answer
99 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 ...
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1answer
108 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 ...
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1answer
102 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 ...
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2answers
751 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 ...
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1answer
216 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
76 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" ...
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0answers
67 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 ...
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1answer
136 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 ...
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2answers
170 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, ...
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2answers
101 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
101 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: ...
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2answers
86 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 ...
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2answers
262 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 ...
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1answer
106 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
119 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 ...
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1answer
118 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 ...
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0answers
211 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 ...
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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 ...
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2answers
78 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 ...
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0answers
256 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. ...
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2answers
798 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 ...
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2answers
104 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 ...
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0answers
91 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 ...
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3answers
232 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 ...
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0answers
364 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 ...
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1answer
163 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
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2answers
158 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
votes
2answers
102 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 ...
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1answer
125 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, ...
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3answers
8k 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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votes
2answers
281 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 ...
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2answers
139 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 ...
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1answer
500 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 ...
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2answers
78 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
134 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 ...
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2answers
277 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
139 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 ...