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Please suggest USB to RS232 adapter that works 100%

Discussion in 'Embedded' started by Tomás Ó hÉilidhe, Jun 13, 2008.

  1. I've purchased one already made by "Cypress Semiconductor" but it
    doesn't work. The VID is 04b4 and the PID is 5500.

    Can anyone suggest a USB to RS232 adapter that does its job perfectly
    100% of the time under Microsoft Windows, i.e. it trully behaves
    exactly just like any other serial port?
    Tomás Ó hÉilidhe, Jun 13, 2008
    #1
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  2. Tomás Ó hÉilidhe

    Guest

    On Jun 12, 8:39 pm, Tomás Ó hÉilidhe <> wrote:
    > I've purchased one already made by "Cypress Semiconductor" but it
    > doesn't work. The VID is 04b4 and the PID is 5500.
    >
    > Can anyone suggest a USB to RS232 adapter that does its job perfectly
    > 100% of the time under Microsoft Windows, i.e. it trully behaves
    > exactly just like any other serial port?


    We've had no end of problems with USB to RS232 adapters
    that only work sometimes, or at certain baud rates, etc. The
    best we've found is Belkin. If you're lucky you'll get one with
    current software. No idea if Vista drivers are available or working,
    but under XP Belkin is OK.

    Hope this helps !
    Best Regards, Dave
    , Jun 13, 2008
    #2
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  3. Tomás Ó hÉilidhe

    Don McKenzie Guest

    Tomás Ó hÉilidhe wrote:
    > I've purchased one already made by "Cypress Semiconductor" but it
    > doesn't work. The VID is 04b4 and the PID is 5500.
    >
    > Can anyone suggest a USB to RS232 adapter that does its job perfectly
    > 100% of the time under Microsoft Windows, i.e. it trully behaves
    > exactly just like any other serial port?


    see:
    http://www.dontronics-shop.com/easysync-premium-gold-usb-rs232-adapter-cable-10cm-cable.html

    I can't guarantee 100%, and nobody can, but this is what it says on my
    advertised page:

    Dontronics Guarantee: These converters are packed in a plastic envelope
    that can easily be re-packed without any damage. If you purchase this
    product, and it doesn't work for you, return it in a re-sellable
    condition, that is, in the same condition that it was delivered to you,
    and will will refund your money in full, provided you return it within 7
    days of receiving it.

    and read the user comments/feed back near the bottom of the page.

    These use the FTDI chips, and in fact are manufactured by FTDI under the
    Easysync brand name.

    Cheers Don...


    --
    Don McKenzie

    Site Map: http://www.dontronics.com/sitemap
    E-Mail Contact Page: http://www.dontronics.com/email

    Intelligent 2.83" AMOLED with touch screen for micros:
    http://www.dontronics-shop.com/product.php?productid=16699
    Don McKenzie, Jun 13, 2008
    #3
  4. Re: Please suggest USB to RS232 adapter that works 100% [ FTDI rocks...and tunnels a serial port through USB ]

    CBFalconer wrote:
    > Tomás Ó hÉilidhe wrote:
    > ... snip ...
    >> Can anyone suggest a USB to RS232 adapter that does its job
    >> perfectly 100% of the time under Microsoft Windows, i.e. it
    >> trully behaves exactly just like any other serial port?

    >
    > Impossible. USB is not a serial port.


    Hi!

    He properly means that he wants to have the RS232 tunnelled through USB
    and showing itselves as a serial port in Windows.


    Look at this ftdi.com based RS232<->serial converter. The VCP drivers
    installed on your PC simply tunnels your RS232 serial port through USB
    to a virtual com-port in e.g. Windows.

    (This was found at the Web-shop: http://www.ftdichip.com/FTProducts.htm ):

    ?14.50, US232R-100 USB to RS232 Converter, 1m:
    http://apple.clickandbuild.com/cnb/...-null&prodCategoryID=4&title=USB RS232 cables
    Quote: "...
    The electronics, including the FT232RQ chip are housed in an attractive
    glossy white enclosure with blue, side-lit LED TX and RX traffic
    indicators. A matching white 1m USB cable uses gold plated USB and DB9
    connectors.

    The US232R-100 evaluation cable is supplied in retail packaging which
    includes instructions together with a Drivers and Utilities CD complete
    with Microsoft WHQL certified VCP drivers for Windows XP. Drivers for
    the Apple Mac, Linux and other versions of Windows are also included on
    the CD.
    ....."

    Cables: UC232R:
    http://apple.clickandbuild.com/cnb/...-products-null&prodCategoryID=45&title=UC232R

    Cables: TTL-232R and variants:
    http://apple.clickandbuild.com/cnb/...goryID=47&title=Cables: TTL-232R and variants

    -

    The FT232BM RS232<->USB chips drivers for many platforms is found here:

    Virtual COM Port Drivers:
    http://www.ftdichip.com/Drivers/VCP.htm
    http://www.ftdichip.com/

    -

    Glenn
    Glenn Møller-Holst, Jun 13, 2008
    #4
  5. Tomás Ó hÉilidhe

    TT_Man Guest

    "Tomás Ó hÉilidhe" <> wrote in message
    news:...
    >
    > I've purchased one already made by "Cypress Semiconductor" but it
    > doesn't work. The VID is 04b4 and the PID is 5500.
    >
    > Can anyone suggest a USB to RS232 adapter that does its job perfectly
    > 100% of the time under Microsoft Windows, i.e. it trully behaves
    > exactly just like any other serial port?



    I've found those with PROLIFIC chip sets work well with my obscure hardware.
    Controlling rts/cts/dsr/dtr correctly is always seems to be the issue.......
    TT_Man, Jun 13, 2008
    #5
  6. "CBFalconer" <> wrote in message
    news:...
    > I'm hearing some objections to my statement above. My point is
    > that USB is a shared system, and that it queues up traffic for
    > transmission at intervals. You can't use the adaptor to respond to
    > an input event in microseconds, as you can with the original port.
    > What you can do is asynchronous transmission and reception, which
    > is most people's objective.
    >
    > For example I believe that the original X-modem protocol will fail
    > miserably. That requires responding to a transmission with an ACK
    > (or NAK) within a very short time. Z-modem will probably work.


    I use X-modem regularly over an FTDI chip and it has never failed.

    Meindert
    Meindert Sprang, Jun 13, 2008
    #6
  7. Tomás Ó hÉilidhe

    David Brown Guest

    Meindert Sprang wrote:
    > "CBFalconer" <> wrote in message
    > news:...
    >> I'm hearing some objections to my statement above. My point is
    >> that USB is a shared system, and that it queues up traffic for
    >> transmission at intervals. You can't use the adaptor to respond to
    >> an input event in microseconds, as you can with the original port.
    >> What you can do is asynchronous transmission and reception, which
    >> is most people's objective.
    >>
    >> For example I believe that the original X-modem protocol will fail
    >> miserably. That requires responding to a transmission with an ACK
    >> (or NAK) within a very short time. Z-modem will probably work.

    >
    > I use X-modem regularly over an FTDI chip and it has never failed.
    >


    It will depend on the level of sharing. If you have an FTDI device
    plugged directly into a root port on your PC, then it will get the full
    12 Mbs for full speed USB. Latency will then normally be of the order
    of a millisecond or two, since that's the polling rate of USB (at least,
    for 12 Mbs USB - I don't know if it is faster for 480 Mbs USB).

    If you share the same root port via a USB hub which is also used for a
    USB memory stick and transfer large files at the same time, you'll see
    far more latency and throughput issues as the bandwidth is shared. How
    much that may affect the serial protocol used depends entirely on its
    timing requirements.

    Even at best, with a direct connection to a root port, USB works with
    timing in the range of a few milliseconds. For most uses, it works fine
    - but as Chuck says it is not going to be 100% identical to a direct
    serial link.
    David Brown, Jun 13, 2008
    #7
  8. On Fri, 13 Jun 2008 03:53:32 -0400, CBFalconer <>
    wrote:

    >CBFalconer wrote:
    >> Tomás Ó hÉilidhe wrote:
    >>
    >> ... snip ...
    >>
    >>> Can anyone suggest a USB to RS232 adapter that does its job
    >>> perfectly 100% of the time under Microsoft Windows, i.e. it
    >>> trully behaves exactly just like any other serial port?

    >>
    >> Impossible. USB is not a serial port.

    >
    >I'm hearing some objections to my statement above. My point is
    >that USB is a shared system, and that it queues up traffic for
    >transmission at intervals. You can't use the adaptor to respond to
    >an input event in microseconds, as you can with the original port.
    >What you can do is asynchronous transmission and reception, which
    >is most people's objective.
    >
    >For example I believe that the original X-modem protocol will fail
    >miserably. That requires responding to a transmission with an ACK
    >(or NAK) within a very short time. Z-modem will probably work.


    I also very much doubt that you could use it with an external
    RS-232/485 converter with data direction control using the RTS line.
    Doing it properly is very hard even on any 14550 style UART,
    especially on any multitasking OS.

    Also implementing Modbus RTU with proper timing is going to be a
    challenge :).

    Paul
    Paul Keinanen, Jun 13, 2008
    #8
  9. Tomás Ó hÉilidhe

    David Brown Guest

    Paul Keinanen wrote:
    > On Fri, 13 Jun 2008 03:53:32 -0400, CBFalconer <>
    > wrote:
    >
    >> CBFalconer wrote:
    >>> Tomás Ó hÉilidhe wrote:
    >>>
    >>> ... snip ...
    >>>
    >>>> Can anyone suggest a USB to RS232 adapter that does its job
    >>>> perfectly 100% of the time under Microsoft Windows, i.e. it
    >>>> trully behaves exactly just like any other serial port?
    >>> Impossible. USB is not a serial port.

    >> I'm hearing some objections to my statement above. My point is
    >> that USB is a shared system, and that it queues up traffic for
    >> transmission at intervals. You can't use the adaptor to respond to
    >> an input event in microseconds, as you can with the original port.
    >> What you can do is asynchronous transmission and reception, which
    >> is most people's objective.
    >>
    >> For example I believe that the original X-modem protocol will fail
    >> miserably. That requires responding to a transmission with an ACK
    >> (or NAK) within a very short time. Z-modem will probably work.

    >
    > I also very much doubt that you could use it with an external
    > RS-232/485 converter with data direction control using the RTS line.
    > Doing it properly is very hard even on any 14550 style UART,
    > especially on any multitasking OS.
    >


    You can do RTS control of RS-485 drivers, but you have even less
    accurate timing with USB than with a standard UART.

    An alternative is to use a feature of the FTDI chips - they can drive a
    RS-485 direction line directly whenever they are transmitting.

    > Also implementing Modbus RTU with proper timing is going to be a
    > challenge :).
    >
    > Paul
    >
    David Brown, Jun 13, 2008
    #9
  10. Tomás Ó hÉilidhe

    James Beck Guest

    In article <9bd63d75-3975-47d3-810a-361318b93f1f@
    34g2000hsf.googlegroups.com>, says...
    >
    > I've purchased one already made by "Cypress Semiconductor" but it
    > doesn't work. The VID is 04b4 and the PID is 5500.
    >
    > Can anyone suggest a USB to RS232 adapter that does its job perfectly
    > 100% of the time under Microsoft Windows, i.e. it trully behaves
    > exactly just like any other serial port?
    >

    Keeping in mind the other posts in this thread AND that your mileage may
    vary; we use, and have never had a SINGLE problem with, the ATEN
    adapters. It may just be luck, or I just haven't tried the magic combo
    that blows it up, but those units have been rock solid performers for
    us. I don't know what chipset the units use and really don't care,
    because they work. They are a bit pricier than most of the crap out
    there.

    Just google or search on amazon:

    ATEN UC-232A

    and you will get plenty of info.
    James Beck, Jun 13, 2008
    #10
  11. I need an RS232 port for the following two reasons:
    * For use with the GT ROM program for re-flashing firmware
    * For programming PIC chips

    The device that Don suggested looks very attractive but I'd just like
    ask one more question:
    My laptop has an "express card" slot. Would I be better off
    getting an RS232 adapter that goes into the express card slot, or
    should I go with the EasySync USB adapter?
    Tomás Ó hÉilidhe, Jun 13, 2008
    #11
  12. "Tomás Ó hÉilidhe" <> wrote in message
    news:...
    >
    > I've purchased one already made by "Cypress Semiconductor" but it
    > doesn't work. The VID is 04b4 and the PID is 5500.
    >
    > Can anyone suggest a USB to RS232 adapter that does its job perfectly
    > 100% of the time under Microsoft Windows, i.e. it trully behaves
    > exactly just like any other serial port?


    I have had the best results with Keyspan. The p/n on the one I use says
    USA-19HS. It is the most reliable that I have used. It has a TI USB3410
    inside with a MAX3243 that I believe is just the RS232 level translator.

    Scott
    Not Really Me, Jun 13, 2008
    #12
  13. Tomás Ó hÉilidhe

    Don McKenzie Guest

    Tomás Ó hÉilidhe wrote:
    > I need an RS232 port for the following two reasons:
    > * For use with the GT ROM program for re-flashing firmware
    > * For programming PIC chips
    >
    > The device that Don suggested looks very attractive but I'd just like
    > ask one more question:
    > My laptop has an "express card" slot. Would I be better off
    > getting an RS232 adapter that goes into the express card slot, or
    > should I go with the EasySync USB adapter?



    I just did a google, as I wasn't sure if they were readily available,
    but found plenty, pricey however. $90USD for this one:
    http://www.usbgear.com/computer_cab...AS1RS&cats=496&catid=1302,496,585,538,464,468

    And I wouldn't know what sort of chip set these or others use. Some
    people may be aware.

    Now have a look at mine:
    http://www.dontronics-shop.com/easysync-premium-gold-usb-rs232-adapter-cable-10cm-cable.html

    Price includes world wide postage. It won't be the cheapest, but it
    works when most of the others fail. That is why I handle them. You can
    speak to the guys that designed the chipset, if you need in depth support.

    Re-read the guarantee of the ability to return the goods if it doesn't
    work for your application. Our loss on postage, all you pay is return
    postage.

    And re-read the customers feed back.
    I think there are 18 responses from Feb 2002, to Dec 2006. I simply
    stopped adding them. Applications that range from Garmin GPS's to Pfaff
    sewing machines. I doubt if anywhere else on the web, you will find a
    report such as this in the way of genuine feed back, on a USB to RS-232
    converter. Please correct me if I am wrong.

    Cheers Don...



    --
    Don McKenzie

    Site Map: http://www.dontronics.com/sitemap
    E-Mail Contact Page: http://www.dontronics.com/email

    Intelligent 2.83" AMOLED with touch screen for micros:
    http://www.dontronics-shop.com/product.php?productid=16699
    Don McKenzie, Jun 13, 2008
    #13
  14. In article <>, CBFalconer <> writes:
    > CBFalconer wrote:
    >>
    >> Impossible. USB is not a serial port.

    >
    > I'm hearing some objections to my statement above. My point is
    > that USB is a shared system, and that it queues up traffic for
    > transmission at intervals. You can't use the adaptor to respond to
    > an input event in microseconds, as you can with the original port.
    > What you can do is asynchronous transmission and reception, which
    > is most people's objective.
    >


    I'll give you another (and probably more relevant for this newsgroup)
    example: the low cost serial port programmers that use the modem and
    hardware flow control signals to drive a microcontroller's onboard
    programming capabilities. See (for example) the serial port based AVR
    programmers.

    USB latency means that there's no way you are going to be able to run
    those over a USB to serial adapter, even if the adapter does a 100%
    accurate implementation of the modem and flow control signals.

    Simon.

    --
    Simon Clubley, clubley@remove_me.eisner.decus.org-Earth.UFP
    Microsoft: Bringing you 1980's technology to a 21st century world
    Simon Clubley, Jun 13, 2008
    #14
  15. Tomás Ó hÉilidhe

    James Beck Guest

    Re: Please suggest USB to RS232 adapter that works 100% [ FTDI rocks... and tunnels a serial port through USB ]

    In article <>,
    says...
    > On 2008-06-13, Glenn M?ller-Holst <> wrote:
    > > CBFalconer wrote:
    > >> Tom?s ? h?ilidhe wrote:
    > >> ... snip ...
    > >>> Can anyone suggest a USB to RS232 adapter that does its job
    > >>> perfectly 100% of the time under Microsoft Windows, i.e. it
    > >>> trully behaves exactly just like any other serial port?
    > >>
    > >> Impossible. USB is not a serial port.

    >
    > Actually it is if one is being pedanting, and this is Usenet so
    > the pedantic flag is set by default. ;)

    How true.
    'U'niverial 'S'erial 'B'us
    Yep, definitely a serial port. :)

    >
    > > He properly means that he wants to have the RS232 tunnelled through USB
    > > and showing itselves as a serial port in Windows.

    >
    > None of the USB->serial adapters (FTDI, Prolific, or any other)
    > will behave "exactly just line any other serial port". The
    > timings and latencies are going to be _way_ different.


    The only BIG problem I have ever had was the fact that most of the
    adapters we tested had some strange glitches occurring on the outputs at
    very consistent intervals. Like 50KHz and ~100KHz on two I recall. I
    presume this was some artifact introduced by the chipset and the polling
    rate of the USB system/driver. In some instances these spikes were
    interpreted as start bits and things didn't go well after that.

    Jim
    James Beck, Jun 13, 2008
    #15
  16. Tomás Ó hÉilidhe

    Guest

    On Jun 13, 9:37 am, Tomás Ó hÉilidhe <> wrote:
    > I need an RS232 port for the following two reasons:
    >     * For use with the GT ROM program for re-flashing firmware
    >     * For programming PIC chips
    >
    > The device that Don suggested looks very attractive but I'd just like
    > ask one more question:
    >     My laptop has an "express card" slot. Would I be better off
    > getting an RS232 adapter that goes into the express card slot, or
    > should I go with the EasySync USB adapter?



    Absolutely. As I mentioned in the other thread, these end up
    providing a real hardware serial port, and behave as such. These are
    available as PCMCIA (AKA Cardbus/PC Card/ExpressCard) cards, as well
    as PCI and PCI Express cards for desktops.
    , Jun 13, 2008
    #16
  17. Tomás Ó hÉilidhe

    Mel Guest

    Re: Please suggest USB to RS232 adapter that works 100% [ FTDI rocks... and tunnels a serial port through USB ]

    James Beck wrote:
    > The only BIG problem I have ever had was the fact that most of the
    > adapters we tested had some strange glitches occurring on the outputs at
    > very consistent intervals. Like 50KHz and ~100KHz on two I recall. I
    > presume this was some artifact introduced by the chipset and the polling
    > rate of the USB system/driver. In some instances these spikes were
    > interpreted as start bits and things didn't go well after that.


    We had a situation with FTDI chips which could have been that one. We saw a
    zero-byte (i.e. \x00) inserted into the data stream every so often. We
    changed our protocol to send an escape sequence instead of a zero byte, and
    strip all zero-bytes on receive, and the system's been behaving well ever
    since. We suspect some kind of timing effect: with the USB side running on
    a 200MHz ARM we got a spurious byte every 1e5 bytes or so -- running a
    600MHz VIA processor we see one bad byte in maybe 1e8.

    Mel.
    Mel, Jun 14, 2008
    #17
  18. Tomás Ó hÉilidhe

    Don McKenzie Guest

    Don McKenzie, Jul 31, 2008
    #18
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