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

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6
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5answers
900 views

Max Serial Cable Length?

What is the maximum length of serial cable I can use, to connection work properly? Is length of serial cable in connection with baud rate? I am using about 5 meter cable at speed 38400 bauds and RS232 ...
0
votes
0answers
10 views

Moxa Mgate3180 485 Communication [on hold]

Problem: Unable to communicate to device on Ethernet end via RS485 (2W). Works fine with RS232. Setup: Computer COM port connected to 232 - 485 device, connected to MGate 3180 ( DB9 wired as per ...
0
votes
1answer
93 views

Has anyone built an rs232 to usb converter?

I want to implement serial communication into one of my projects, but I'm hesitant to use a serial cable due them them being exceedingly hard to find nowadays. I found an old converter and took it ...
0
votes
1answer
51 views

STM32 RS485 connection

I want to interface stm32f0 with rs422 (half duplex and full duplex). What I'm not getting how to connect RE and DE signals to rs 232. From UART I'll be having RX, TX, VCC and GND pins which i need to ...
1
vote
0answers
45 views

RS232 to TTL converter problem

I have a RS232 to TTL Converter which has 4 pins Vcc, Tx, Rx, GND . I am trying to make a serial communication with my PC. I have a AVR development board and I have tested my program by connecting ...
0
votes
2answers
46 views

Serial, RS232, Modbus, UART and TCP

I want clearly know this, Serial is protocol right? Then what is the Modbus? Is it under serial. And what are RS232 and RS485? What is UART and serial and UART same? What about TCP? TCP and serial ...
-1
votes
0answers
6 views

How to communicate with two PC using RS232 [migrated]

I was just wondering that is this possible to communicate with two computers using RS232 using softwares like docklight and putty. Suppose if i send Hi from on pc will it recive in another PC and ...
0
votes
1answer
31 views

RS232-TX voltage translator

Would like your help to clear my doubt and confusion for this circuit http://nil.rpc1.org/wordpress/?p=31. I don't get a sense that how possible the RS232-pin3 TX signal is converted and transmitted ...
0
votes
1answer
69 views

How to transmit data from an analog multiplexer to an RS232 COM port on a PC

I am having trouble understanding how to design a circuit that will transmit multiple analog data signals to a computer through one RS232 COM port. The analog data is a simple voltage reading from ...
2
votes
1answer
458 views

Max232 giving incorrect values at pins

Background: I'm trying to connect a Compact Logix PLC -> MAX232CPE Maxium chip -> arduino. Currently my PLC does communicate modbus RS232 with a request for data from the arduino. I can see this by ...
0
votes
3answers
70 views

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 : ...
0
votes
3answers
98 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 ...
0
votes
1answer
39 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 ...
0
votes
2answers
91 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 ...
0
votes
4answers
97 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 ...
0
votes
1answer
59 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 ...
-1
votes
1answer
59 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 ...
0
votes
3answers
84 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 ...
0
votes
1answer
61 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
votes
0answers
30 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 ...
0
votes
1answer
225 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, ...
0
votes
0answers
35 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
votes
0answers
21 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
votes
0answers
22 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
votes
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?
0
votes
2answers
71 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 ...
0
votes
0answers
52 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. ...
2
votes
2answers
292 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 ...
0
votes
1answer
88 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 ...
0
votes
3answers
164 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
votes
1answer
48 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
386 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 ...
-1
votes
2answers
281 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
votes
1answer
41 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 ...
0
votes
3answers
84 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 ...
-1
votes
3answers
251 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 ...
0
votes
0answers
90 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
votes
1answer
157 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 + ...
0
votes
0answers
245 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
votes
3answers
116 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
vote
1answer
633 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 ...
0
votes
2answers
188 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 ...
0
votes
0answers
58 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
votes
4answers
136 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
votes
1answer
57 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 ...
1
vote
1answer
141 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
votes
0answers
263 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 ...
1
vote
3answers
154 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
votes
1answer
192 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
94 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 ...