RS-232 is the electrical standard used on most serial ports.
2
votes
0answers
67 views
Need help with a sub-standard RS232
I've built a UART-RS232 converter based on max232 and it works well... but not for what I need :)
According to Maxim's datasheet the RS232 side signal voltage should be theoretically +/-10v (5v * 2), ...
0
votes
1answer
80 views
How to reduce a noise on a serial line
I have set up serial communication between my Arduino and a sensor stamp.
The sensor stamp in question is Atlas Scientific EC stamp.
The communication uses RT232 RS232 serial protocol.
The replies ...
0
votes
1answer
64 views
How to send ASYNC 8,N,1 serial data over an SPI interface using two Arduino Uno boards
Need help with sending ASYNC data between two Arduino UNO R3 micro-controllers.
System design follows:
RS232 modem 19,200,8,N,1 --> UNO-1 D0=(rx), D1=(tx). RS232 parameters cannot be changed because ...
2
votes
1answer
87 views
Selecting communication between microcontrollers at high temperature
I have been assigned to a project to find the best possible communication between several PCB boards which have microcontrollers for a specific function. I need to have all microcontrollers ...
1
vote
2answers
94 views
Color code for DB-9 Connecter
I have an old DB-9 connector (Male-to-Female). I cut it in half, to find 6 wires inside. 5 Had colored insulators and one was a strand of naked wires.
First question: isn't it supposed to have 9 ...
0
votes
0answers
41 views
Communication between PTZ camera and an embedded board
I have a PTZ camera which has a serial Communication Port RS-232C and I want to connect it to a single core embedded system which has an Ethenet and USB.
How can I make the connection between the PTZ ...
1
vote
4answers
162 views
Different ASCII Characters in RS 232
I'm working on the UART communication of PIC18F4520. I have tried simulating the code on ISIS proteus and then also checked the real time result. One thing I am quite confused about is that the ...
0
votes
0answers
76 views
UART controller scheme with detalization
I'm trying to find a UART controller scheme. I guess it will be something like the image below, but I need more details: at least, I need all the components (registers, counters and so on) that every ...
-1
votes
2answers
112 views
How to interface a com port on cash register? [closed]
I am trying to interface a se-52000 cash register. The com2 port is free and it is usually used with a barcode scanner. I want to sent data(something like barcode scanner emulation data) from a ...
6
votes
4answers
190 views
Recommendation of a USB to RS232 chip for industrial environment
I have bought a device which has a ATMega microcontroller and a FTDI chip which connects to a computer through USB. The FTDI is used only as RS232 to USB adapter.
My problem is that this device ...
2
votes
2answers
127 views
Disadvantages of USB to RS232 dongles
I understand (or am learning, rather) how both RS232 and USB work. What I am really curious about, and can not seem to find much information for, is what kind of disadvantages do USB to RS232 dongles ...
1
vote
1answer
53 views
Calculate sum check
I'm trying to send some serial commands.
In the manual of the hardware it says:
Sum check byte is the summation of all bytes. Higher order bytes are ignored and and the final result is modified. Bit ...
0
votes
2answers
144 views
RS 232 serial sniffing
We have a task in hand to sniff a RS232 protocol in a certain industrial automation setting(we have been asked to do this legally by the manufacturing company itself). We are planning to send a ...
0
votes
2answers
106 views
How to implement Serial port RS-232 from 2.5V IO signal?
I am playing with a Xilinx Spartan-3A development (XC3S50A-TQ144C) and then I tried to implement RS-232 serial port by following the guide here: http://www.fpga4fun.com/SerialInterface.html
I bought ...
5
votes
1answer
132 views
How to connect RS232 (“Opto-RS232”)
--Background--
I'm setting up a pretty standard RS232 interface from a digital caliper to a microcontroller, via a MAX232 chip (or in my case, MAX3222, which is the 3.3V-supply variant with 2 ...
2
votes
1answer
194 views
Interfacing barcode scanner with microcontroller
I am doing a project involving barcode scanner, netduino plus 2(microcontroller). I came across different types of interfaces(pin standard used such as USB etc..) for barcode scanners which are ...
5
votes
0answers
91 views
How to use SCPI on HP33120A via RS232?
I have old Hewlet Packard 33120A function generator (it should be the same type as Agilent 33120A) and I would like to control it with MCU (ATMega). The generator has RS232 and use SCPI commands.
I ...
4
votes
1answer
189 views
Why MAX232 works without any capacitors?
I was playing today with a very simple setup of pic16f876 and max232 connected to the COM port of a PC running a terminal emulator. I was just testing (the uc simply echoes anything it receives) when ...
0
votes
1answer
82 views
Communicating by RS-232
I'm trying to communicate with a serial barcode scanner. This is how i've linked it to my computer (the circles represent the color of the wires already soldered in the serial plug) :
When I scan a ...
1
vote
2answers
67 views
How to send data from external device to OS with rs232 and fake it as a mouse
I have a project that i need to send some data with an RS232 to USB cable from external Msp430 launchpad to the computer and fake it as a mouse. Is this possible without learning USB protocols of the ...
1
vote
2answers
223 views
Connecting RFID reader with RS232 interface to an arduino
I am attempting to detect 134.2kHz RFID tags using a chip from Priority 1 Design, specifically this one
I am attempting to connect this to an arduino Uno, but I am not really sure where to start. ...
-2
votes
1answer
154 views
Remote controlled RS232 switching
A mission critical fire alarm system has a GSM module that is connected via RS232 to a computer whose task is to notify emergency response teams. In case the computer fails, an off-site operator is ...
3
votes
2answers
220 views
Serial Port (DB9) signals
Just about every time I use a serial port for anything, I only use 3 pins of the usual 9-pin connector (DB9): Tx, Rx, and GND. And when I wire up my microcontroller projects to these ports, I just ...
4
votes
3answers
234 views
Square wave -5 to +5 volt at 500 Hz
I need to make a square wave -5 to +5 V at approx. 500 Hz - with small current. I have 0 (ground) and +5 V and a PWM (a Waspmote with a ATmega1281 microcontroller). I think it would be possible to ...
0
votes
1answer
213 views
Hardware flow-control (CTS/RTS)
My MCU cannot wake up from UART data, so I wanted it to wake up from the RTS line, but Im having problems understanding the concept.
When Im sending data from my MCU to the peripheral, I see the ...
2
votes
3answers
330 views
How to transmit ASCII over RS-232?
i want to display the voltage level through a Potentiometer over the serial comm line(RS-232) in pure ASCII. I am trying to do this using MC9S08AW60 on the Board-DEMO9S08AW60E.
So, if the ...
-2
votes
1answer
108 views
Interpret answer of serial connection [closed]
I sniffed some package transfer via COMP1 (RS232) which I can not interpret.
As RAW data it looks like:
<00><08><44>@<45>@?<F8> ... ...
0
votes
1answer
66 views
PIC24f16KL402 skipping values at serial port
I am trying to write the values of a counter on the serial interface, just to test the interface.
The problem is that only every second value (2,4,6,8,...) is received by the desktop. I use port PORTA ...
0
votes
2answers
989 views
Receiving input from RS232 and reading it with Arduino board
Let me begin by stating that I don't have much experience in hardware-related projects.
I need to obtain info from a machine that outputs its data from an RS232 cable.
http://i.imgur.com/fkqnf.png
...
0
votes
1answer
122 views
Questions about RS-232-like naming and standards
1. Is official RS-232 (EIA-232) standard open and free available? I couldn't find it in Internet.
2. Does "RS-232 with TTL levels" is covered by some standard?
3. Does "synchronous RS-232" (via ...
3
votes
1answer
215 views
What serial signalling format is this? (RS-485?)
This is a mystery signaling standard that I'm trying to sort out. It looks more or less like RS-485 to me, but I don't recognize the long looking start bit, and the "idle" state of the line looks a ...
1
vote
1answer
259 views
How to detect RS232 and USB connectivity?
My project involves a PIC communicating over USB and RS-232 channels, which are then multiplexed to 1 UART by means of a dual SPDT analog switch. As such, the PIC has to know which ports are ...
1
vote
1answer
139 views
rs-232 theoretical maximum speed
I've read that speed of rs-232 depends on length of cable. There are many different tables that describe this dependency. But speed although should depend on voltage of Rx and Tx signals. How maximum ...
2
votes
2answers
1k views
Can't figure out EIA-232 (RJ45) to DB9 cable… (seems simple!)
I've purchased a used BayTech RPC4 unit (8-port power strip controllable using RS232).
The front of the unit has an RJ45 port (EIA-232) and has a wiring diagram on how to wire it to a DB9 port so you ...
0
votes
0answers
70 views
Working with arbitrary CMOS signals (2.5V - 5.5V)
I am trying to build a simple CMOS-RS232 convertor for my uC boards to be interfaced to a PC. I am using a MAX232. The board has to be able to be hooked to any uC board. I use AVR-s, ant they work at ...
0
votes
0answers
127 views
RJ12 to DB9 RS232 for DELL standby power supply
I'm hoping someone can point me in the right direction. I've got a 1000W DELL SPS (an UPS by another name) and it's got an RJ12 for comms.
Under the hood I've found pin 1 goes to ground, 5, 6 goes to ...
4
votes
2answers
236 views
Interfacing 3V TI MSP430 to PC serial port
I am scratching my head to figure out a possible soloution for this scenario:
I am developing a simple application using TI MSP430 microcontroller. The microcontrol part is powered by 2xAA batteries. ...
0
votes
4answers
285 views
Embedded web server recommendations
I have some sensor hardware that outputs serial data and want to make it into an internet appliance.
Essentially, RS232 -to- Wifi, embedded on a web server. Like routers are designed. So that I can ...
0
votes
2answers
288 views
RS232 to UCB using cp2102 chip
Long times ago I bought on the ebay a cheap rs232->usb converter, today I wanted to use but I realized that I don't have the pinout. This is the converter how can I figure it out the pinouts, does ...
0
votes
1answer
114 views
Inaccuracy of a RS-232 baudrate
I write a simple software implementation of UART for my ATtiny. My CPU isn't fast, so I should choose low baudrate. Nevertheless I want to use as high baudrate as possible. And I can estimate the ...
2
votes
1answer
390 views
China bluetooth modules and RS232c with RTS/CTS
I've been having a lot of fun (mostly using other people's instructions) with some of those cheap bluetooth modules (via ebay specials) from China. I'm just getting my feet wet learning the actual ...
0
votes
1answer
108 views
TTL RS-232 current limiting
I'm making software UART (TTL levels) on ATtiny85. Need I connect current-limiting resistor to output (TX) port? If "yes", what value should I use?
I plan to connect my device to a UART-USB converter ...
0
votes
1answer
235 views
Connecting RS232 output of Lattice XP2 Brevia Kit to PC USB (virtual COM port over USB) using a FTDI RS232RL based board
I have a Lattice Brevia XP2 Kit (the older one that came out in 2010/2011, and the not the newer version 2). The only PC connectivity it has is through serial (rs232). I have anetbook that does not ...
4
votes
3answers
198 views
Replacing a custom serial port connector with a Micro-USB 2 plug
I currently have a very fragile solution to connect my embedded device to a PC's serial port. This is mounted on the PCB: http://www.digikey.com/product-detail/en/DF13A-6P-1.25H(50)/H3384-ND/530681. ...
2
votes
1answer
362 views
How to connect USB barcode scanner to a PIC?
I've got a bog standard barcode scanner with a USB output and I'm trying to figure out how to connect it to a PIC.
Basically, the idea is that I use the scanner to scan a barcode and the barcode is ...
0
votes
2answers
402 views
Arduino serial communication with printer
I'm working on a project with an Arduino Mega 2560. I connected the board to a MAX232CPE in order to communicate in serial mode with a thermal printer.
I connected the MAX232 to one of the 3 extra ...
-3
votes
3answers
276 views
RS232 concurrent communication [closed]
I need to interface with a printer equipped with a RS232 port from both my arduino microcontroller and my computer. It means that the printer is connected to the computer through the RS232 port and I ...
3
votes
2answers
153 views
RS-232 and RS-485 software configurability?
I would like to connect a anemometer(RS-485, DB9) to the PC. The PC has a serial port with DB9 connector. I couldn't find the specification of the serial port. Is that RS-232 standard or RS-485? Most ...
2
votes
1answer
91 views
Why does it hase a power supply for the rs232 to rs422?
We have a anemometer with RS422/485 communication, and we would like to connect to the PC, but we have only RS232 so I would like to purchase a converter, but some converter has an external power ...
1
vote
3answers
517 views
For connecting two micro which one is better, UART or RS232?
I'm trying to connect two devices which in both of them use pic micro. I am curious to select best connection solution. I can use uart for connection between them and also with helping of MAX232 rs232 ...
