IT Answers » Serial ports

Visual Basic 6 problems with RS-232 communications

Vfafou — Thu, 11 Aug 2011 12:04:16 +0000

Hello! I have 2 problems with Visual Basic 6 mscomm32.ocx serial communications activex:

1. I’m having a new generation pci RS-232 interface with FIFO-UART 16950 and I face the problem that I can’t receive all incoming strings, but a part of them.

2. My application supports up to 6 RS-232 ports with mixed settings. I mean that the two ports are opened with BAUD 9600 and two others with BAUD 4800. It is possible to receive the same thing from all ports simultaneously but I want to process it one time. If it is being received from a port with BAUD 9600 and a port with 4800, then it is coming with a time difference and I can’t reject the one and use the other. I think that I have to make a receiving queue but I don’t figure out how could it be.

Any suggestions?

Thank you in advance!

VB6 and VB.NET Serial (COM1) data error

Aattanayake — Thu, 03 Feb 2011 04:29:00 +0000

Hello,
I’m new to .NET. I have an application that is running in VB6. It sends text through COM1 port to another device.

When I converted the VB6 code to .NET the string it sends out is different! I have tried so many things and don’t know what to do. I used a serial data analyzer and found the two strings are different even the the source code is the same.

VB6 source code:
MSComm1.CommPort = 1
MSComm1.Settings = “9600,O,8,1″
MSComm1.PortOpen = True
MSComm1.Output = Chr(&H2B) & _
Chr(&H4) & _
Chr(&H3) & _
Chr(&HE8) & _
Chr(&H0) & _
Chr(&H2) & _
Chr(&HF6) & _
Chr(&H71)
MSComm1.PortOpen = False

The analyzer gets the following string in hex: 2B 04 03 E8 00 02 F6 71

VB.NET source code:
Dim Port As SerialPort = New SerialPort(“COM1″, 9600, Parity.Odd, 8, StopBits.One)
Port.Open()
Port.Write(System.Convert.ToChar(&H2B) & _
System.Convert.ToChar(&H4) & _
System.Convert.ToChar(&H3) & _
System.Convert.ToChar(&HE8) & _
System.Convert.ToChar(&H0) & _
System.Convert.ToChar(&H2) & _
System.Convert.ToChar(&HF6) & _
System.Convert.ToChar(&H71))
Port.Close()

The analyzer gets the following string in hex: 2B 04 03 0F 00 02 3F 71

Why is there a difference in the string?
Please help me correct it…
Thanks

how to use parallel port for serial communication

Amna — Wed, 12 May 2010 11:52:36 +0000

i want to use parallel port for spi. i dont know how to set phase and polarity for sclk.how to send and recieve data. do i need to shift data synchronized with the clock or the parallel port will do it automatically?

How do I use the serial port in Sun virtual box with Windows XP

Leerporter — Thu, 07 May 2009 22:51:43 +0000

Ok here is my question. I have a windows host and another windows VM (XP). In the VM I want to access the serial port, com1, but it asks me to give the port path, I get lost there.

RS-232 Port Buffer – Hardware protection

Flame — Wed, 11 Mar 2009 13:35:29 +0000

I am looking for a device that attaches between the RS-232 port on a computer (in this case a laptop) and a Serial device (in this case an old programmable logic controller) that acts as a signal buffer. I’m NOT looking for something that stores data, rather I’m looking for a device that will protect the port on the laptop from spikes as well as improperly wired or damaged ports on the PLC machines. I’m looking at making my own, with a ZIF socket so that a damaged buffer chip (probably a MAX232) can be swapped out quickly, but I don’t want to re invent the wheel is a similar device exists.
Thanks!

Cisco’s 2500 series router and WAN card serial interface differences

NetworkingATE — Thu, 05 Feb 2009 22:24:22 +0000

What is the difference between the serial interface of 2500 series Cisco routers and the serial interface of WAN cards (WIC-1t)? If there is no difference then is there any data-rate difference between the above two serial interfaces?

VMware Server on Linux – COM / Serial Port Issues

David Davis — Mon, 17 Nov 2008 22:01:28 +0000

We recently received the following question through the www.SearchServerVirtualization.com “Contact Us” Email address:

I am running VMware on a linux machine.
I cannot communicate through serial port COM1 when working in VMware.
It says " Unable to connect to port COM1".

Is there any specific setting that needs to be done to use serial port
COM1 while using VMware on a linux machine?

Can you please help me out with this issue?

Here is my recommendation-
While I haven’t personall run across this, I would recommend two things if/when I do-
1. I would first make sure that you can USE the com port in Linux with a real device (ie: the com port could be disabled in the BIOS of the server)
2. I would check my VMX file serial port settings to make sure that they are correct. This document has some great reference on that-

http://sanbarrow.com/vmx/vmx-serial-ports.html

Thank you,
David Davis, VCP
Train Signal.com VMware ESX Video Training Author – www.TrainSignal.com
www.VMwareVideos.com

Location of Management LAN port

Aprakash — Mon, 17 Nov 2008 17:47:31 +0000

Which is better, a serial port on the front or back of a server/switch device for initial configuration and when the device is not working.

RS 232 is there any differance between( RS232 ) and (RS232-C) protocols

Sami — Sun, 06 Apr 2008 05:51:48 +0000

hello,
is there any differance between( RS232 ) and (RS232-C) protocols??
please tell me details if possible…..

thanks a lot …..