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Serial port not present, USB is, Need access to COM1

I have a Pentium III Dell Latitude laptop running W2K which does not have a serial port on it.  It does have a USB port.  I have a piece of equipment (an LXD75 telescope) which has a serial port plug that can be connected to a PC through the serial port.  I bought a serial port to USB port cable, but it seems that the PC doesn't see the COM port.  I know the scope works because it works with the desktop which does have a serial port.

I cannot see any COM ports under device manager/ports.

I can see COM1, COM2 & COM3 if I go in through the add printer wizard.

How can I get this laptop to undertsand that COM1 traffic should go through the single USB port?

Heck, how can I create a COM1 port so it'll be seen by the device manager program?

Rich
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RichNH
Asked:
RichNH
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1 Solution
 
Irwin SantosComputer Integration SpecialistCommented:
who makes the LXD75 telescope? does it come with a utilty to configure?
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garycaseCommented:
Nice scope :-)   It's been over 20 years since I had a telescope, and this question brings back many fond memories of stargazing with my son.

Many USB-serial adapters don't properly translate all of the serial control signals, particularly with laptops, which can have barely compliant USB power available.   You could try a different USB-serial adapter, or (better) you can buy a PCMCIA card with a serial port, which will for sure have all of the control signals available.   This card has two ports:
http://www.newegg.com/Product/Product.asp?Item=N82E16815158011

If you want to just try another USB adapter, this has good reviews from the previous purchasers:
http://www.newegg.com/Product/Product.asp?Item=N82E16812156008

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Irwin SantosComputer Integration SpecialistCommented:
@garycase... richnH has a laptop....
http://www.cdw.com/shop/products/default.aspx?EDC=520863

The above is the more appropriate product
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garycaseCommented:
irwinpks -- that would be why I made the comment "... particularly with laptops ...", and is why I linked to a PCMCIA card ==> in fact, the exact same card you linked to -- except my link has it for $60.00 + 3.99 shipping;  yours has it for $66.99 plus $12-$15 shipping (so your link is about $15 more expensive)      :-)  :-)


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Irwin SantosComputer Integration SpecialistCommented:
you're right I must've been seeing things.
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Zuhir ElgmatiCommented:
dell web site have great support ....so i suggest to enter there and check your model of your Latitude ( coz you don't give us the model )  service manual and guides ....or search for troubleshooting there ....belive me you will get the solution... visit www.dell.com or chose your model from this page and start searching for your issue http://support.dell.com/support/systemsinfo/documentation.aspx?c=us&l=en&s=gen&~cat=12&~subcat=87
or give us your model ...and i will bring you the solution .....

good luck
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RichNHAuthor Commented:
The model # I pulled off the label on the bottom of the laptop says it is a PMP.  Latitude CS series.  I guess I always thought that the COM1, COM2, COMn ports were more software designations than hardware designations.  The device itself (the telescope) has its own computer in the handbox which is what the cable connects to.  Since its a serial device already, is there a lot of need for power?  I knew that the USB ports also had power flowing through them to power the devices, I thought the serial ports didn't have power.  The telescope has its own power supply and fully powers up on its own.

When I look at the XP desktop that I've plugged the scope into before and where it did work, and I look under device manager/ports, I see a COM1 port.  I don't see that on the laptop.  Shouldn't there at least be a COM1 port on the laptop?  It seems like COM1 doesn't even exist yet.  I'm confused.

What should I expect to see on the PC when the adaptor is fully working?

The PCMCIA card is a bit more expensive than the cable (which cost $25).  I probably won't spring for that option since the laptop itself is an old one belonging to the company I work for, I'm just borrowing it.  One thing this exercise highlights for me is that if I do get my own laptop, its going to have a serial port on it! :-)

Rich

PS. The full designation for the telescope is a Meade LXD-75 10" Schmidt-Newtonian and it IS a nice scope! :-)
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ridCommented:
The COM ports are usually hardware ports on the mobo or an add-on card. Most BIOS's search for four hardware serial ports at certain I/O addresses. Normally, a desktop PC used to have 2, laptops one (and one dedicated to IR port). In DOS and windows, these ports are called COM1 through COM4, depending on how many are found on the system (e.g. Linux calls them someting else).

If you absolutely need to use USB and convert to RS232, you must have a software that fools the O/S into using the USB port as a virtual COM port (not a very good solution in many cases); if not you get a proper serial port for your system (a PCMCIA adapter card).
/RID
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Zuhir ElgmatiCommented:
ok try to use this great tool from dell ,it's tool to find the problems of hardware ,   Dell™ Diagnostics:
http://support.dell.com/support/edocs/Systems/pmac/en/en_ug/diag.htm
and use PC scan tool :
http://support.dell.com/support/topics/global.aspx/support/dsn/en/entry?c=us&l=en&s=gen
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garycaseCommented:
I'm well aware it's a Meade scope -- I was drooling over it last night :-)

The serial port doesn't have a dedicated voltage supply pin like a USB connector, but it does require voltage to operate.   There are 6 control pins, each of which must be at either -12v or +12v to indicate their current state.   Many USB-serial adapters do not support hardware flow control; but I would still expect the PC to "see" a COM port, so you may simply have a defective adapter, or it may require a driver you don't have installed correctly.

Did the USB-serial adapter come with any driver software?   What is the specific make/model of the adapter?

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garycaseCommented:
I've not used this, but USBGear has a good reputation, and this USB-serial adapter specifically notes that they support all of the signaling lines:  http://www.usbgear.com/USBG-232MINI.html
Note that it does require drivers (which come with it).
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FermionCommented:
My first thought would be to go ahead and force a COM port assignement through ADD NEW HARDWARE/Ports/ComPorts.

According to rid, though, this may not work.

Still, I would try that. If it doesn't work, no harm is done and you can always delete the newly created COM port.
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FermionCommented:
Forgot to mention: You said that it works on a desktop with true serial ports. OK, be sure to note the I/O address that works and match it on your laptop when you create the COM1 port.
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PUNKYCommented:
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chiingliangCommented:
I dont' think you have a serial port. Just get a usb-serial converter that cost around 20usd
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RichNHAuthor Commented:
I tried a number of different ways to get this to work, none worked.  Therefore I returned the cable and will pick up a PCMCIA card.  Thanks all for the contributions.

Rich
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catoaguilarCommented:
Connect another device (like an usb memory stick) to your USB port to see if it is really working. If not, check the bios to see if it is disabled.

If other devices work OK, but the usb to serial adapter is not seen as a serial port then you may check it on another computer to verify if it is working OK. You may need a driver CD to install the adapter.
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