Thread: New laptops with serial ports?

  1. #1
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    New laptops with serial ports?

    I've been given a $1500 budget to spec out a laptop for my new job. The only real requirement I have is that it has a working serial port for programming older PLCs. I don't really trust USB to serial adapters because I've heard about cases where they don't work, don't follow the standard, etc. I read that the PCI card (ExpressCard, PCMCIA) versions provide true RS232 compliance though and are a better alternative.

    Anyway, does anyone know of any laptop lines that offer actual serial ports? If not, has anyone had to program chips or PLCs with a serial adapter of some sort and how well did it work?

    Thanks

  2. #2
    Master Apprentice phantomotap's Avatar
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    My advice: give up on finding a modern laptop with a real RS232 port and driver, contact a hobby group for any information they have about the best current chips to use for RS232 controllers from a USB port, and then find a commercial dongle that uses that chip.

    The Arduino community has never steered my wrong when it comes to that flavor of discussion.

    Soma

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    I take it you'll need the serial port in the field, and solutions that provide it from the docking stations are no good?

    From what I understand, a lot of laptops do have the circuitry but opt to only expose it from a docking station. I know that ThinkPads are like that, as well as HP Pro- and EliteBooks. Can't say for other makes and models.
    Disclaimer: This post shows my ignorance at the time of its making. I claim ownership of but not responsibility for all errors in it. Reference at your own peril.

  4. #4
    Master Apprentice phantomotap's Avatar
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    From what I understand, a lot of laptops do have the circuitry but opt to only expose it from a docking station.
    Do any builders actually do that anymore?

    My Lenovo era "Thinkpads" don't have RS232 on any docks; all extra ports not USB were audio or video related. Last I checked, a couple years ago, Toshiba had stopped offering RS232 on docks in favor of offering dongles.

    This isn't a "I know more than you post!" by the way; I'm asking if you know of any specific cases because it would take a while to look through every dock for every laptop from every builder.

    From IRC: "ftdi all the way single or doubles only the four port models are missing lines"

    Soma

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    I'm in the same situation that I have to program a lot of kinds and versions of PLCs. The last 10 years or so I have used Thinkpads.
    For the rather rare situations where a usb to serial converter didn't work I use the docking station.
    My experience tells that fiddling with the portsettings helps most of the times. Normally it means switchig off or reducing the buffer size.
    A much bigger problem are the cases where the programming software won't run on any modern hardware or OS. And believe it or not there are PLCs still running that I have setup in the early nineties.
    BTW The ThinkPad I use right now is less then a year old and the dock still has the RS232
    Kurt

  6. #6
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    Thanks guys. I also heard that USB to serial adapters with the FTDI chips supposedly work very well. Not sure if I want to spend money on a dock or not though.

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    I've used FTDI chips in quite a few projects (I design my own circuits + PCB) and they always work reliably, and have cross platform drivers.

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    Quote Originally Posted by phantomotap View Post
    Do any builders actually do that anymore?

    My Lenovo era "Thinkpads" don't have RS232 on any docks; all extra ports not USB were audio or video related. Last I checked, a couple years ago, Toshiba had stopped offering RS232 on docks in favor of offering dongles.

    This isn't a "I know more than you post!" by the way; I'm asking if you know of any specific cases because it would take a while to look through every dock for every laptop from every builder.

    From IRC: "ftdi all the way single or doubles only the four port models are missing lines"

    Soma
    I won't be able to verify my statement about ThinkPad docks, but for HP see here. At a quick glance, at least 3 of those models have a serial port, male DE-9, specifically.
    Disclaimer: This post shows my ignorance at the time of its making. I claim ownership of but not responsibility for all errors in it. Reference at your own peril.

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