Questions tagged [rs232]

RS-232 is the electrical standard used on most serial ports. Note that this standard is a +/- 15 volt system and requires a FDMI converter to make it compatible with TTL logic levels.

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40 views

RS232/CAN switch circuit

I am working on a communication switch that is digitally controlled and I am using four MUX506IPWR from TI to choose the output channel. The switch has on the input a DSUB9 for a CAN channel and a ...
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UART communication with a Thorlabs chip

I am trying to configure a Thorlabs temperature driver (MTD415TE), using a UART-USB connection. For this, I am using a Foca v2.2 with a FT232R USB-UART cable. I am using serial terminals such as ...
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XPort Edge (web manager) access denied with default credentials

I have the Xport EDGE connected and powered using the evaluation board. I'm trying to use an XPort EDGE as a means of connecting an embedded device to the internet. It uses RS485 (That's the ...
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36 views

Frame Errors (Character Stretching) of CP2102N

When I send a data stream from my PC to a CP2102 USB-to-Serial Bridge, the data coming out of the RS232 side is sometimes corrupted. The receiving micro (an ATmega2560) reports frame errors when this ...
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RS232 Communication Voltage Level

I understand that RS232 Communication voltage levels should be between 3 and 25 Volts for positive voltages and the equal negative for negative voltages, but is there a source that can explain the ...
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70 views

Garbage on RS232 and no the baudrate IS correct

I have a device like this https://www.vaisala.com/sites/default/files/documents/WXT530-Users-Guide-M211840EN.pdf. Some facts: I have an FTDI to USB board from Sparkfun which is tested to work with ...
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Confused with PC RS232 pin-out for this stepper motor communication

I'm planning to communicate with the module of a servo motor. The manual is given here. At page 88 there is a diagram for RS232 wiring as shown below: The manual mentions in the motor side pin3 must ...
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47 views

ICL3232 and SN75C3232 difference

I'm using ICL3232EIV-16Z-T in one of my projects for UART communication. As per the datasheet, the max speed is 500Kbps. But I've tested this IC for baud rate up to 921600 and there is no data loss. ...
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Flashing LPC1769 with FlashMagic

I'm encountering problems flashing my LPCxpresso1769 with FlashMagic. I had previously been able to get it to work using a USB to UART lead (TTL-234X-3V3) and powering the device externally (i.e. ...
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75 views

is it possible transfer an image via rs-232 serial-port cable? [closed]

*I want to take an image from a medical device. Should I take the data first and then visualize it in pc via another program?
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1-channel GPIO from industrial PC over RS232 port

I am ordering a computer based on 4x4-R1000V motherboard (Ryzen Embedded, https://www.asrockind.com/overview.asp?Model=4X4-R1000V) for an industrial application. I need a 1-channel GPIO (0 for zero, >...
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56 views

RS232 Modbus to USB wiring

I have a RS232 device that sends data following the modbus protocol. I have problems communicating with it and I think my wiring is wrong. Since most modbus devices work over RS485 it is hard to find ...
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FTDI (FT232R) chip holding the RX line high

The issue that I am having is that the device won't communicate. I have traced the problem down to the RX line on the FTDI chip holding itself high and not letting signals through. I have spent a ...
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MON08 RS-232 Programming Interface

I'm trying to build a MON08 interface to program a 68HC908QB8, as per page 13 of this PDF: Low-Cost Programming and Debugging Options for M68HC08 MCUs Below is my schematic, from which I have ...
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35 views

RS232 Serial Console: Do we receive serial packets at serial pin out from CPU even we don't have the console cable connected?

What if I don't have the serial cable connected to the serial port, still I receive serial packets from CPU? (lets say console output is enabled in Software) Will those packets got terminated (...
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Modbus RTU over RS232 link

I am designing a convertor board that will interface three device with Modbus RTU RS232 port to a Modbus RTU RS485 network. Slaves supports Modbus RTU, but their ports is different from master port. ...
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68 views

How to handle RS-232 grounding when connecting multiple devices?

I need to connect multiple devices using RS232 in a ring where the TX of one device goes into the RX of the next device. I will use a copper cable for the physical layer. I can't use RS485 that ...
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How can I connect multiple modules/devices to one single usb port

Currently I have one GSM IOT-GA6 module connected to my laptop using a CP2102 usb adapter. Currently im able to communicate with the device sending AT commands using ...
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86 views

Scrambled Data on a RS232 port

I currently face a problem of scrambled data on one of our RS232 connections to a serial terminal and would like to request some help, if possible. Sent: Received: First of all some information ...
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4answers
197 views

RS232 Voltage Level Boosting

I have a piece of old instrument circa 1988 that uses +-12V in its serial port. According to the manual, DTR pin (Data Terminal Ready) must be held at +8V in order for the instrument to recognize that ...
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1answer
74 views

RS-232 to RS-485 transceiver

I'm new in communication protocols and ICs. I would like to know if it is possible to connect a RS-232 (TX, RX and GND) to a RS-485 (Vcc, A, B and GND). I only need a half-duplex communication. The ...
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251 views

Modbus RTU using SoftwareSerial

Im trying to control a temperature controller using Arduino MEGA over SoftwareSerial. Im using Modbus-Master-Slave-for-Arduino library and I tried to test using example code below. It gives only <...
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1answer
130 views

Connect to a serial output device with 12V power input with 5V USB-TO-UART

I have DG600F coin acceptor with 12V power input and serial port output CP2102 usb-uart bridge and FDTI TTL-232RG cabel as an alternative A PC and Macbook as alternative I need to connect DG600F to ...
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72 views

How to identify 422 or 485 bus from the PCB

I have a very old CPU card, maybe 1980's. It has following chips on it and most probably these are used for communication with the rest of the system. SN55188 Quad Line Drivers SNJ55189 Quad Line ...
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3answers
106 views

Connecting 2 external PCBs with a 1m cable

I would like to connect 2 PCBs. On each PCB there is a MCU and each MCU is able to send and receive commands from the other one. Also, PCB1 should supply power to PCB2. The 2 PCBs are separated by ~...
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60 views

RS232 to ethernet over LAN

Can I connect an rs232 Ethernet converter to a switch and expect to receive a data on a php server listening to the of IP conversor? In windows I need to install drivers to create a virtual com, so I ...
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289 views

RS422 and RS485; full-duplex or half-duplex?

I have extensively used RS232 transceivers in many projects and have fairly good understanding of UART communication using RS232 transceivers. MAX232 and MAX3232. Now I have to build my understanding ...
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694 views

RS-232 to I2C communication [closed]

I'm trying to establish communication between two boards, one of which has an RS232 output and the other with an I2C input. I've looked for adapters online and the only ones I've found seem to be ...
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1answer
82 views

Comparing MAX3232 vs MAX232 for line length

Which parameter in the datasheets of the line drivers MAX3232 and MAX232 can tell about the maximum length of the line for their correct operation if all else is same for the two circuits, that is ...
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3answers
233 views

MAX232 Replacement

I have a circuit where a 12V square wave signal (a Profile Ignition Pickup signal from a Ford EDIS ignition module) was fed to an MCU via a MAX232 chip. My understanding of the MAX232 is that the ...
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1answer
107 views

Connector Identification on Instrument

I have a piece of instrument made around 2000 with a connector to computer that I cannot recognize. Can someone help me out? It is a 20-pin connector, with 10 pins on each row. Pictures are here: ...
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2answers
209 views

RS232 Unusual “Framing Error”

I have an old piece of instrument that suppose to connect with a Windows XP machine. I keep getting "Framing Error" messages on the instrument panel while the PC side shows that the instrument could ...
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1answer
96 views

Detect an unknown communication protocol and read data on it

We have old type textile machinery in our factory. (open end machine) on the machine's screen is showing the operating efficiency of the machine. Under the hood, When I follow the cables, the sensors ...
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63 views

What specs does the “gros condo” (big capacitor) needs to have?

I have a pair of Dynaudio Air 20 at home. Unfortunately, the cable that used to control the speakers via RS232 died. I opened the cable, and saw that it was a customized RS-232 to TTL adapter, but ...
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26 views

Logic leves and protocol, interfacing HP39GS to arduino Wemos D1

Im trying to connect HP39GS scientific calculator to Wemos D1 arduino. It has TTL RS-232 serial port. Pinout is somewhat: Vcc, TX, RX, GND. Looks like HP39GS protocol for serial port is not pure RS-...
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411 views

Transmission from atmega32 to PC using max232 not working

Transmission from atmega32 to PC using max232 not working. When I checked the data from the Tx pin (in the realterm software) of atmega32 it was fine. But there was no output data from max232, when I ...
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101 views

Protecting RS-232 from overvoltages

I am using Some arduinos (5V Pro-Mini, but planing to move to actual ATMEGA chip) over a distance of few metres. These are connected using standard Alarm cable (I had problems with Ethernet cable and ...
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1answer
157 views

How to monitor one wire “kind of” protocol

In the current network, there's 1 master device, which gathers data from over 20 devices. Nameplate says the baud rate is 2400. In the bus cable there's one data wire, 12V and GND. A friend of mine ...
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91 views

GSM Modem Transmission Issue

I'm having a problem getting this GSM modem to work with an FPGA (Spartan 3). I've already implemented UART transmission on the FPGA side,the MAX232 to convert TTL->RS232, and 3.3V->5V logic level ...
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2answers
197 views

RS485 vs RS232 similarity vs differences

I have used UART RS232 communication between MCUs extensively. Now I need to interface my STM32F407 MCU over RS485 bus with with devices. I have understood few things about RS485 but not-clear about ...
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2answers
79 views

MAX232 vs TRS202EC Line Drivers

I have used MAX232 as UART serial line driver using 5V power supply. Now I have come across TRS202 chip in a circuit. It also run with 5V power supply. Does this chip has some special difference or is ...
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1answer
151 views

RS-232 interface chip problem - why is the voltage level so wrong?

1. What I want to do: I have a PCB with an AVR microcontroller (ATmega16U4) on it. I want the microcontroller to communicate with my computer through an RS-232 cable. 2. What I did: I added an ...
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What is this weird behaviour I am observing with doing a loopback around MAX3232?

So this is my pretty little circuit that I made. AFAIK all connections are fine and I have tested them using multimeter for any shorts. I was actually testing the circuit by loop back shorting J1's ...
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57 views

Serial communication between raspberry and laptop not giving right values

I want to communicate between a Raspberry Pi 3 model B and a laptop using a USB to RS-232 cable and this RS-232 to 3.3V TTL converter via the serial module in Python: GND is connected to board pin #6 ...
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2answers
468 views

Can a MAX232 IC be used for RS-232C standard?

I have a GT01 Panasonic LCD which it's interface is RS-232C. I have read that the difference between RS-232 and RS-232C is their voltage level which it's ±5 V in RS232C. Can I use a MAX232 IC to ...
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Is there a standard describing the UART data frame protocol?

The "U" in "UART" stands for "Universal", but I'm having trouble finding any standard that describes the framing protocol that's used in UART; e.g. the start bit, stop bit, parity options, and baud ...
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RS232 Data Format “Design” Questions (from non-EE) [closed]

I've been tasked with defining a format for (asynchronous) binary RS232 data sent from one device to another. These are mostly error messages and some engineering data from a custom autopilot device ...
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865 views

What's the difference between a null modem cable and a gender changer? [closed]

Please ignore this question. It doesn't address the problem I was trying to solve (XY problem) and my edits have been reverted. Because it has answers, I can't delete it. It should be closed as off-...
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minimalist serial port addon to a basic 8052

Currently I have two microcontrollers connected to each other so that I have two serial ports. One to the PC and one to a wireless radio module. Now I'm considering replacing one microcontroller with ...
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1answer
123 views

Does this wiring pattern for a DB9 cable exist as a standard cable?

I have a scientific instrument that uses a DB9 cable to connect to the standard RS232 port on a computer for communication. I've deconstructed one of the cables as I needed to make another one but I ...

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