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

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PIC MCU to PC Serial Communication Problem

I was just trying to send continuous stream of letter 'G' from my PIC MCU (PIC18F452) to my laptop. Here is my assembly code that i am using : ...
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3answers
64 views

What is a 3 wire type cross linked serial cable?

I'm trying to use a controller which uses Serial communication with the PC. The documentation says I need to get a 3 wire type cross link serial cable. Is this a null modem cable? The following ...
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1answer
37 views

How to transfer data between RS-422 and RS-485 ports? [closed]

I'm relatively new to behaviors of serial ports such as RS-232, RS-422, and RS-485. I'm wondering how do you initiate data transmission between a system and a device connected to each other thru one ...
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1answer
56 views

“Unable to open parallel port I/O driver” when trying to connect “RS232 to USB” cable on Linux

I have a JDM programmer for pic micro-controllers, but it came with RS232 port. I have bought a "RS232 to USB" cable with its driver for Windows only and I use Xubuntu 14.04 LTS. I have tried ...
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4answers
57 views

Why use MAX232 when using USB-to-Serial cable

I was wondering the need to use MAX232 type ICs when using a USB to RS232 converters. A prolific based converter gives the following output, when transmitting 'a' It seems to me that a simple NOT ...
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1answer
40 views

Questions about an atmega32 serial-bus to RS232 with converter and different logic levels

I have an atmega32 and a FUM DCF-U atomic clock (signal receiver and decoder) of HKW-elektronik. The ยต-controller works with 5V and the module on 3.3V. I have to build a converter, because the ...
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1answer
43 views

RS232 ISP programming

I have a saleae digital analyzer and i am using it to listen to on a ISP programmer. (not to steal someone's code, but to build my own programmer). It only has two wires (GND & SDA) The data just ...
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2answers
47 views

How to program an ATMega328 using a Serial Port without using programmers such as USBasp

I am currently learning electronics. I recently bought an ATMega328 and an USBasp programmer to begin my learning. But I couldn't use the USBasp to program my chip. So I researched on other ways to ...
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1answer
50 views

Simple Interrupt Handling program?

I'm new to Embedded programming and I'm trying to understand how Interrupt handlers work in different contexts/scenarios. I just want to know how a interrupt handler would work in the following ...
0
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0answers
22 views

Why are RI and DSR signal combined in TIA-561 (RS-232 over RJ-45)?

EIA/TIA-561 is the standard for transmitting RS-232 signals over an RJ-45 modular jack instead of the more familiar DB9 connector. I'm getting most of my information from here: Zytrax They have this ...
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1answer
86 views

Serial Communication with rs232/485 and rj45

I am working a project where I want to connect and control, using Labview, TDK-Lambda Power Supply Process Vacuum Controller Ion Gauge (MODBUS interface) They both have rs232/rs485 capabilities, ...
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0answers
25 views

how to connect light transistor to serial out

I want to be able to communicate between two computers through a laser. On the laser's side, I have a raspberry pi turning it on and off. On the receiving side, I want to somehow connect a ...
0
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0answers
18 views

ZULU-M RF Transceiver

I am attempting to send simple ASCII characters between two RF ZuluM868 modules. It uses a Low level Rs2323 so I am using a terminal program with a USB to 3v rs232 level converter. I have followed the ...
0
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0answers
21 views

Consumer IR receiver on RS-232 port without DCD

I want to build a CIR receiver for OMAP3530 SoC running Linux. I hope to be able to use LIRC library for this task. There's just one problem: the recommended IR receiver schematic uses DCD pin of the ...
6
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5answers
2k views

Why is USB cable maximum length is shorter than in RS232?

Why do we need to buffer USB signal if the cable is longer than 5m? Is that because a signal voltage drop? Is that because it drives currents?
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2answers
49 views

Generate TTL-level reset pulse from RS-232 level signal

(My knowledge of analog circuit design is severely limited). I am trying to generate a reset pulse for an AVR microcontroller. The reset is active LOW, and the maximum threshold voltage is 0.9V, with ...
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0answers
38 views

Is some protection necessary for a RS232 link between PIC-MAX232-Computer?

I have a circuit with a dsPIC which communicates to a computer using a MAX232 (there ain't any optical isolation). The circuit ground is not bounded to the earth. But the equipment case is earthed. ...
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2answers
257 views

How to protect a MAX232 from PIC programming high voltages?

This question is derived from this Board review thread, I thought it would be preferable to make it a standalone question. I want to be able to reset a PIC remotely using the only communication port ...
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1answer
85 views

Board review: is this PIC16F877 RS232+ICSP board correct/robust?

I want to make my own development board based on a PIC, to make a RS232 bootloader from scratch. It's been a while I haven't used a PIC, and it was on a ready made development board. I've looked ...
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3answers
102 views

RS232 non-inverting level shifter

I am starting a project that will end up as an RS232 wireless bridge (XBee radios) and have no idea where to find the chip I am in need of. I'm currently in the testing phase without the radios to ...
0
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1answer
42 views

Partial load failure detection circuit

I'm working on the power supply of a temperature controller which sends about 5kW of power maximum (230VAC 50Hz) into 3 sets of 12 heaters (actually, 3kW + 1kW + 1kW). I'm at the stage where I need to ...
2
votes
1answer
360 views

UART as logic analyzer?

I'd like to reverse-engineer a certain 2-wire digital circuit. I'm looking for the cheapest possible logic analyzer. I don't know the exact frequency of the circuit, but it's sub-1MHz. (Likely in the ...
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2answers
152 views

SIM900 - USB- TTL Communication from PC

I do have some doubts about the communication of the SIM900 GSM module with the PC. By default the GSM module has the RS232 connection to interface with PC. source:link But my PC has only USB ...
0
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1answer
34 views

serial data from avr to python

I am using ATtiny2313 microcontroller along with a RS232 to establish communication between my microcontroller and the laptop. Here's my question : What is the predefined system for the laptop to ...
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3answers
79 views

usb to rs232 to usb

I have a system where there is usb slave device that is in a rotating structure behind a slipring. I need to pass the signal through the slipring (we only have 4 "wires") and onto a computer. Due to ...
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3answers
173 views

Is MAX232 is needed?

I'm planning to send data from my laptop via Hyperterminal to Arduino's TX RX pins. Normally RS232 is around +12V -12V; but I will use a USB to RS232 converter as in the figure below: And from a ...
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0answers
66 views

GSM SIM900A Board and USBtoSerial

just got my SIM900A board same as Connecting GSM SIM900A module with Ardunio and I am trying to connect it to my USB-rs232 converter. I couldn't find any doc on module itself, has anyone done it? Tnx ...
0
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1answer
123 views

Programming 16F84A With K8048 software & a custom Hardware (With CH340 USB2Ser)

After reading Manoj's Work about how to program some PICs with USB to Serial Adapter, I decided to try myself to program the 16F84A with my CH340 USB-SERIAL adapter Materials : Software : Cygwin + ...
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0answers
205 views

RFID card reader : wiegand 26 bits but UID tag 40 bits?

I am working on a project of access control with a Raspberry Pi. I want to buy a RFID card reader (125 khz) and tags. After a lot of research on the web, I found out that the most common connection ...
0
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3answers
107 views

Problem connecting two RS232 [closed]

I have a device with a RS232 communication port (3 pin,tx,rx and gnd). When I connect it to a PC RS232, they don't communicate together. I use hyper terminal on the PC side and all setting are ...
1
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1answer
480 views

Interfacing barcode scanner with arduino using RS232

I want to connect a barcode scanner with Arduino. I used MAX232 to convert the levels. I have taken only 3 pins: 2(RX), 3(TX) and 5(GND) from the DB9 cable and given them to pins of MAX232 as shown in ...
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2answers
176 views

Switch a Transistor ON/OFF with Txd Line From USB2SER Adapter (CH340)?[Resolved]

Note/Update: The Problem was The Use of an extension cable (RS232 Null Modem Without Handshaking).So, The RxD & TxD are inverted.it means if you want to measure TxD voltage You should Get it from ...
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0answers
50 views

when to cascade Modbus TCP/RS-485 gateways?

I've noticed that many Modbus Gateways support cascading. Cascading makes sense, when converting from TCP to RS-232 since RS-232 allows 1 transmitter/receiver on each line. But does it make sense ...
2
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4answers
124 views

Why there are data bit lower than 8 data bit of uart

Our group are creating a UART IP Soft Core with Wishbone Wrapper and we are using 5,6,7 and 8 data bit. I just want to know what are the use of the 5, 6 and 7 data bit? In addition to my question ...
0
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1answer
52 views

TTL-level camera with MAX3232 installed - is that really TTL-level or an RS232-level?

I've just recycled an LCF-23T CMOS camera (http://www.thaieasyelec.net/index.php/Sensors/Light-/-Imaging/4dsystem-JPEG-Color-Camera-UART-TTL-Interface-OV528-Chip/p_177.html) that the vendor describes ...
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1answer
134 views

Serial Link Between 3.3V devices

I have an RPi and a freescale FRDM-KL25z controller which will talk over serial protocol. I'm using the pyserial library on the pi: ...
0
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0answers
218 views

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
138 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 ...
0
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1answer
149 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 ...
0
votes
1answer
82 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 ...
1
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1answer
81 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 ...
1
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1answer
133 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 ...
1
vote
2answers
5k 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 ...
1
vote
1answer
293 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 ...
0
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0answers
77 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
684 views

How can RS-232 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 ...
0
votes
2answers
153 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
91 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
votes
1answer
128 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
votes
1answer
361 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 ...