The RS232 and RS485 serial port has its share of problems. Some of them are inherent while others arise during its usage. The intrinsic ones are constituted by its limitations, while the ones that occur when being used are spontaneous. This means that the RS232 / RS485 serial port has 'an already predicted' problem (the inherent ones) and problems that are unforeseeable. These unpredictable problems, however, occur very frequently and should therefore be seriously considered.
The most common problem, that happens to be a part of the RS232 and RS485 serial ports, is its mode of transmission. It can only send single bits of RS232 data which makes communication very slow. This can be a major problem, especially when its being used in a busy environment, and easily brings a lot of dissatisfaction. The good news is that this problem can be solved by the use of an intermediate RS232 / RS485 data link peripheral interface UART. UART (Universal Asynchronous Receiver-Transmitter) is an integrated circuit which contains software that converts single bit data format into 8-bit stream of parallel data. This enhances the speed of RS232 communication between two devices, and, in turn, facilitates the processing of RS232 data.
Another problem that is experienced by users of the RS232 / RS485 ports is the absence of flow control (hand shaking) or its misconnection. This usually results to communication lock-up or buffer overflows. These buffers are usually called FIFO because they occur in a first-in first-out mode. The only way to minimize this problem is by using UART. The UART has trigger levels which indicate the number of bytes of information that can be sent to it from the computer. The computer communicates with the UART devise and access the time that the buffers in it can be refilled. With good RS232 communication between these two (the computer and the UART) these buffer overflows can be greatly reduced. This relates to both RS232 and RS485.
The third problem, which is likely to be experienced, using RS232, is incorrect communication between DTE and DCE devices. This result in some handshaking lines or even the reversal of receives and transmits RS232 data lines. The RS 232 link cable between the two devices is usually the cause of this problem. The solution to this problem is to disconnect the RS232 cable until the problem is over. This is done because the problem might have arisen due to a wrong connection of the RS232 cable.
The fourth problem that is faced by many users of RS232 to RS485 ports is incorrect pin configuration, or finding it hard to deal with the serial ports' connector genders. This makes it hard for people to 'mate' or connect any devise that uses this kind of connecters. This is because some devises have 25 pins while others have 9 pins, some are male some are female. As a result, some people get frustrated with these devises and some end up not using them. To solve this problem, people can use intermediate cables such as RS232 DB9 gender changes or custom made cables. These cables help in connecting devises with different numbers of pins -on either the female or the male connector-and hence make it easier for the users.
Thursday, October 28, 2010
Monday, August 16, 2010
Improved USB Serial RS232 Adapter
New improved USB Serial adapter, XetaLinx:
http://www.usconverters.com/index.php?main_page=product_info&cPath=67&products_id=290
You will like it! :-)
http://www.usconverters.com/index.php?main_page=product_info&cPath=67&products_id=290
You will like it! :-)
Wednesday, July 14, 2010
Wednesday, June 23, 2010
Five Important Features of Quality USB to Serial Converters
Universal Serial Bus (USB) ports have become very popular and most new computers come installed with two or more. Users are comfortable with the advantages of USB’s plug and play and with the variety of peripheral devices that can be easily connected. However, there are still many legacy devices, especially in industrial automation environments, where RS232 (and RS422 / RS485) serial connectivity works just fine. It is for these devices that USB to RS232 converters are ideally suited.
Here are five important features to look out for before choosing a supplier’s USB converter product.
Feature #1: Support for Microsoft Vista and Windows 7 Operating systems.
Although most manufacturers supply drivers for earlier Microsoft system software, as well as for Apple Mac and Linux, there have been performance issues with some manufacturers’ converter products and Microsoft’s newer releases that show up as screen freezes, crashes and connectivity problems.
Solution: Check that the converter comes with drivers that have been optimized for these two Microsoft offerings. (For more detailed information search online for info on Microsoft’s “Windows Hardware Quality Lab” (WHQL) and “Virtual Com Port” (VCP)).
Feature #2: Protection Against Electrostatic Discharge (ESD)
If the operating environment is prone to voltage spikes and surges then a USB converter that protects against ESDs of up to 15 kV and against current surges of up to 600 W/ms is a wise investment. Make sure your USB to RS232 or USB to RS485 converter is designed for these tough conditions.
Feature #3: Supports A Range of Converter Product Offerings
It’s important that your supplier is able to understand the marketplace and provide various converter solutions to satisfy it. For example, some customers require only mini USB to RS232 or USB to RS422 converters, while others insist on multiport, industrial-grade converter hubs. A supplier that can support a range of USB converter products most likely is serious about delivering excellent products and customer service. While this may seem like a ‘soft’ feature, and more on the marketing side, it can be the decider if you have to choose from more than one supplier.
Feature #4: LED ‘Lights On’ Management
While this may not be necessary on the cheaper, single port converters, for multi-port USB to RS232 converter hubs, it’s a useful feature to have when first troubleshooting possible connectivity issues.
Feature #5: Compatible with USB 2.0 and compliant with USB 1.1
Most newer computers come with USB 2.0 ports but there are still those that have only the older USB 1.1 ports. Engineers showing up on-site with older notebook computers may appreciate this backward compatibility one day!
Taken together, when these five features are found in a USB to Serial converter product you can be confident that the device has been engineered to perform to a high standard.
Here are five important features to look out for before choosing a supplier’s USB converter product.
Feature #1: Support for Microsoft Vista and Windows 7 Operating systems.
Although most manufacturers supply drivers for earlier Microsoft system software, as well as for Apple Mac and Linux, there have been performance issues with some manufacturers’ converter products and Microsoft’s newer releases that show up as screen freezes, crashes and connectivity problems.
Solution: Check that the converter comes with drivers that have been optimized for these two Microsoft offerings. (For more detailed information search online for info on Microsoft’s “Windows Hardware Quality Lab” (WHQL) and “Virtual Com Port” (VCP)).
Feature #2: Protection Against Electrostatic Discharge (ESD)
If the operating environment is prone to voltage spikes and surges then a USB converter that protects against ESDs of up to 15 kV and against current surges of up to 600 W/ms is a wise investment. Make sure your USB to RS232 or USB to RS485 converter is designed for these tough conditions.
Feature #3: Supports A Range of Converter Product Offerings
It’s important that your supplier is able to understand the marketplace and provide various converter solutions to satisfy it. For example, some customers require only mini USB to RS232 or USB to RS422 converters, while others insist on multiport, industrial-grade converter hubs. A supplier that can support a range of USB converter products most likely is serious about delivering excellent products and customer service. While this may seem like a ‘soft’ feature, and more on the marketing side, it can be the decider if you have to choose from more than one supplier.
Feature #4: LED ‘Lights On’ Management
While this may not be necessary on the cheaper, single port converters, for multi-port USB to RS232 converter hubs, it’s a useful feature to have when first troubleshooting possible connectivity issues.
Feature #5: Compatible with USB 2.0 and compliant with USB 1.1
Most newer computers come with USB 2.0 ports but there are still those that have only the older USB 1.1 ports. Engineers showing up on-site with older notebook computers may appreciate this backward compatibility one day!
Taken together, when these five features are found in a USB to Serial converter product you can be confident that the device has been engineered to perform to a high standard.
Tuesday, June 1, 2010
USB to RS232 Converters – An Introduction
Many people are familiar these days with the use of universal serial bus [USB] ports on their desktop, laptop and notebook computers. The widely used USB 2.0 specification supports a 480 Mbps transfer rate and is popular because computer users can easily connect a wide range of consumer electronics devices and computer peripherals to their computers without having to configure 'dip switches' or install dedicated interface boards.
Although the 'plug'n'play' functionality of USB is its greatest benefit over older and cumbersome ways of connecting and configuring devices, there are still devices that do not support (or physically have installed) USB ports, but do possess RS232 serial ports.
Here is where USB to RS 232 converters have a role to fulfill by connecting computer and RS232 peripheral together.
However, there's more to successfully connecting, for example, an RS232-enabled GPS phone to a computer's USB port, than just manufacturing an appropriate cable. Sophisticated converter electronics plus operating system dependent device driver software are, in addition to the cable itself, what make up a reliable USB to RS-232 converter.
The reason for this complexity lies partly in how software engineers and application programmers have interpreted and coded for the RS232 specification over the years.
The complete details are beyond the scope of this article but in essence the fact that the RS232 specification defines only the interface, and not the protocol to be used, has given implementers a lot of freedom.
Bottom line: application or operating system device driver ways of communicating with RS232 ports introduced a 'flexibility' which does not appear in the more inflexible USB interface specification.
This means that communicating with RS232 via a USB port introduces the requirement for RS232-style UART device driver emulations. So we now have two device drivers involved over a USB Bus with the potential for timing conflicts that can interrupt and delay RS232 communications.
On the hardwire side, there are known issues with various RS232 line driver chips that can result in RS232 input port behavior outside of the original specification.
Another problem that can show up in cheap USB to RS232 converters is an inability to perform the hardware flow control required by some (but no all) applications.
Of course, identifying which applications use software flow control and which use hardware flow control is often beyond the knowledge of the converter manufacturer. And the application itself may make irregular and unclear use of hardware flow control.
The lesson here is to pay careful attention to how the USB to RS232 converter handles application timing, RS232 signaling and hardware flow control. This is particularly important in industrial automation scenarios, although don't be surprised to also experience irregular issues with poorly designed converters in office computing locations.
In contrast, the leading USB to RS232 converter manufacturers use well regarded processor chips in their top end products, such as those from FTDI Semiconductors. They also provide simple to install device drivers supporting popular operating systems such as Windows (including Windows 7 and Vista), Linux and Mac.
Visit USconverters.com to find out more about RS232 to RS485 converter products, free Tools and Diagnostic software.
Although the 'plug'n'play' functionality of USB is its greatest benefit over older and cumbersome ways of connecting and configuring devices, there are still devices that do not support (or physically have installed) USB ports, but do possess RS232 serial ports.
Here is where USB to RS 232 converters have a role to fulfill by connecting computer and RS232 peripheral together.
However, there's more to successfully connecting, for example, an RS232-enabled GPS phone to a computer's USB port, than just manufacturing an appropriate cable. Sophisticated converter electronics plus operating system dependent device driver software are, in addition to the cable itself, what make up a reliable USB to RS-232 converter.
The reason for this complexity lies partly in how software engineers and application programmers have interpreted and coded for the RS232 specification over the years.
The complete details are beyond the scope of this article but in essence the fact that the RS232 specification defines only the interface, and not the protocol to be used, has given implementers a lot of freedom.
Bottom line: application or operating system device driver ways of communicating with RS232 ports introduced a 'flexibility' which does not appear in the more inflexible USB interface specification.
This means that communicating with RS232 via a USB port introduces the requirement for RS232-style UART device driver emulations. So we now have two device drivers involved over a USB Bus with the potential for timing conflicts that can interrupt and delay RS232 communications.
On the hardwire side, there are known issues with various RS232 line driver chips that can result in RS232 input port behavior outside of the original specification.
Another problem that can show up in cheap USB to RS232 converters is an inability to perform the hardware flow control required by some (but no all) applications.
Of course, identifying which applications use software flow control and which use hardware flow control is often beyond the knowledge of the converter manufacturer. And the application itself may make irregular and unclear use of hardware flow control.
The lesson here is to pay careful attention to how the USB to RS232 converter handles application timing, RS232 signaling and hardware flow control. This is particularly important in industrial automation scenarios, although don't be surprised to also experience irregular issues with poorly designed converters in office computing locations.
In contrast, the leading USB to RS232 converter manufacturers use well regarded processor chips in their top end products, such as those from FTDI Semiconductors. They also provide simple to install device drivers supporting popular operating systems such as Windows (including Windows 7 and Vista), Linux and Mac.
Visit USconverters.com to find out more about RS232 to RS485 converter products, free Tools and Diagnostic software.
Friday, May 14, 2010
The Truth About USB to Serial RS232/RS485 Adapters
Most newer electronic devices can be connected and communicate with a computer by a USB cable, however many devices are still using the older type of communication protocol called serial RS232 or RS485. To connect devices with a Serial RS232/RS485 port you need an adapter cable called a USB to RS232 adapter or USB to RS485 adapter, depending on if your device is using the RS232 protocol or the RS485 protocol.
USB to RS232 or RS485 adapters are often used for connecting devices such as GPS navigation units, sensors, meters, loggers, cameras, printers and other standard and special devices to a personal computer.
Most people assume that these adapters are compatible with ALL operating systems and ALL devices, however this is far from the truth.
When you invest in a USB to Serial adapter you usually pay for what you get. Many websites are selling low-cost USB to Serial RS232 adapters for $9.95. This sounds like a great deal, however when you receive the adapter and connect your device to your computer you will most likely get disappointed, because in most cases the adapter will not work properly with either your computer or your device. The major reason for this is that the low-cost adapter is made with a low-cost processor chip. These low-cost processor chips have limited compatibility with the majority of devices and the Microsoft Windows operating system.
Limited compatibility means that the adapter/drivers might or might not work with your Vista/7 computer, it all depends on your computer's particular hardware, installed Windows components and service packs, conflicting drivers or other peripheral devices, and even your processors bios version.
Usually the drivers work fine with Windows 98, 2000 and XP, however when it comes to Windows Vista and Windows 7 the problems starts showing.
The drivers for a low-cost USB to Serial the processor chip are very often poorly written programs which makes the adapter unstable and unreliable and not fully compatible with Windows 7 and other current operating systems. Because of this you will in many cases be unable to make a low-cost adapter work with Windows 7 and Vista and you can expect some of the following typical errors:
- Computer freeze
- Invalid debug DLL
- Computer crashing
- Driver problems
- Unable to connect to your device
- Unable to establish a COM port
So what do you need to look for to find a good quality USB to RS232 adapter?
First of all you need to determine which operating system you will be using the adapter with. Windows 98, 2000, XP, Vista, 7, or maybe Mac or Linux. If you are using Windows 98, 2000, XP or Linux you might be lucky to find a low-cost adapter which will work for you, however if you are using Windows Vista, 7 or Mac you need to be willing to spend between $20 - $30 for a good quality adapter which will work with your device and Windows Vista/7. Try and find out what processor chip is inside the adapter, good processor chips are FTDI, Silicon Labs, MosChip or Oxford Semiconductors. If you find a USB to Serial RS232 adapter with any one of these processor chips it will most likely be compatible with your device and any version of Windows, Linux and Mac, and you will be able to easily install the drivers and communicate with your device.
To learn more about serial communication, products and support please go to www.USconverters.com
USB to RS232 or RS485 adapters are often used for connecting devices such as GPS navigation units, sensors, meters, loggers, cameras, printers and other standard and special devices to a personal computer.
Most people assume that these adapters are compatible with ALL operating systems and ALL devices, however this is far from the truth.
When you invest in a USB to Serial adapter you usually pay for what you get. Many websites are selling low-cost USB to Serial RS232 adapters for $9.95. This sounds like a great deal, however when you receive the adapter and connect your device to your computer you will most likely get disappointed, because in most cases the adapter will not work properly with either your computer or your device. The major reason for this is that the low-cost adapter is made with a low-cost processor chip. These low-cost processor chips have limited compatibility with the majority of devices and the Microsoft Windows operating system.
Limited compatibility means that the adapter/drivers might or might not work with your Vista/7 computer, it all depends on your computer's particular hardware, installed Windows components and service packs, conflicting drivers or other peripheral devices, and even your processors bios version.
Usually the drivers work fine with Windows 98, 2000 and XP, however when it comes to Windows Vista and Windows 7 the problems starts showing.
The drivers for a low-cost USB to Serial the processor chip are very often poorly written programs which makes the adapter unstable and unreliable and not fully compatible with Windows 7 and other current operating systems. Because of this you will in many cases be unable to make a low-cost adapter work with Windows 7 and Vista and you can expect some of the following typical errors:
- Computer freeze
- Invalid debug DLL
- Computer crashing
- Driver problems
- Unable to connect to your device
- Unable to establish a COM port
So what do you need to look for to find a good quality USB to RS232 adapter?
First of all you need to determine which operating system you will be using the adapter with. Windows 98, 2000, XP, Vista, 7, or maybe Mac or Linux. If you are using Windows 98, 2000, XP or Linux you might be lucky to find a low-cost adapter which will work for you, however if you are using Windows Vista, 7 or Mac you need to be willing to spend between $20 - $30 for a good quality adapter which will work with your device and Windows Vista/7. Try and find out what processor chip is inside the adapter, good processor chips are FTDI, Silicon Labs, MosChip or Oxford Semiconductors. If you find a USB to Serial RS232 adapter with any one of these processor chips it will most likely be compatible with your device and any version of Windows, Linux and Mac, and you will be able to easily install the drivers and communicate with your device.
To learn more about serial communication, products and support please go to www.USconverters.com
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