COM Port Mystery

[K5MBV]

I have this problem and see on MANY forums and in MANY
posts that others do also. There have been no shortage of the obvious things to try, but no real answer that
anyone admits working.

Not just in one program, but several different programs
have the same dificulty and it doesn't seem to have ever been resolved. My
faith in computer gurus is fading.

OK here it is: When the program is first opened the following msg appears "Can Not Open COM Port x" (Where x is the port assigned to the radio for CAT control via a serial to USB converter.) The driver is working and no matter which port is assigned, the same msg appears.

Does ANYONE have THE solution to this very common problem?

Ken  K5MBV

[N3OX]

"Does ANYONE have THE solution to this very common problem? "

There is no one solution.

"Cannot open COMx" is not a specific error message, it's a very general one that means the link isn't working.

It could be that you have a dud USB <-> RS232 converter

It could be that you have a dud RS232 <-> CAT (ttl serial) converter

It could be that there's a setting wrong somewhere.

If you've checked all the settings and drivers, sometimes all you can do is swap out the hardware.  

I've heard a lot of stories about how people can just never get their USB<->Serial converter to work right.  I don't know why it happens, but I guess manufacturers aren't building them and writing the drivers to be 100% compatible with the software, hardware, and the communications standards.  

I use a direct converter from USB to TTL Serial (0V Lo 5V Hi) that can interface directly with the CAT port on my FT-857D.

http://www.sparkfun.com/commerce/product_info.php?products_id=8165

It uses a FTDI FT232RL chip with drivers that seem to work very well with Windows XP.

I can't speak directly for any other combination of converter, radio, and operating system, but I have heard generally good things about the FTDI chipset, and it eliminates the need for a double conversion (USB to RS232, RS232 to TTL).


73,
Dan

[K3AN]

If you're using Windows Vista you can add that to the list of potential trouble sources.

[K5MBV]

Thanks Dan, these are good answers. I have tried several adapters. At least two of them use the
FTDI chip set and driver. I've tried all hardware
changes that are possible with no good results. I've
now got about 6 USB to serial converter cables and
I think four of them use the same driver. Either
Prolific or FTDI are the only drivers that came with them.

I do believe the problem is a setting somewhere that
has been overlooked or software corruption. There is
no problem with the same hardware on the serial to USB
link to my rotors. They work fine. I've tried swapping
adapters and drvers between rotor and radio. They all
work for the rotors and none for the radio. I haven't
tried disabling the rotor port to see if it could be used
for the radio because I'm afraid to lose rotor control. I may have to use another computer for the
radio port. This problem like others might be cured
by a simple setting change or some other simple hardware reconnect, but what it is escapes me.

Ken  K5MBV

[K5MBV]

by K3AN on September 6, 2008    
"If you're using Windows Vista you can add that to the list of potential trouble sources."

You got that right!  
 

[AB3BO]

Try
>>Control Panel>>Device Manager>>>Ports(Com&Lpt)>>
Whatever usb (mine is prolific usb-to-Serial Comm Port (ComX)>>Port Settings>>Advanced>>Com Port Number and Assign the lowest available com port number to the port.

I am using Com Port 2.

Works fine for me. On Vista!

AB3BO -Don-

[K5MBV]

Don, you think I haven't tried that....at least ten
times!

The lowest COM port not shown as used is COM port 17.
COM port 16 is the one used by the rotors. COM 17 doesn't work. Disabling COM port 1 or 2 or 3 and
asigning them as the radio port doesn't work
either. These answers have been posted before and
none of them have worked. I have no idea what the
first 15 COM ports are being used for.

Whatever the problem, you haven't experienced it. I didn't either for the rotors.

Ken

[K5MBV]

Just for the record, I even tried a Yaesu FIF-232
converter box thinking that maybe my RS232 to TTL
cable was bad and this was somehow being reflected back to the PC.

NO COM port will open but COM 16 which is
used for the rotors. I doubt it would work for the
radio and I don't want to chance losing rotor control.

I need to hear from someone who has had this problem and has found a solution!

Ken  K5MBV

[AB3BO]

Usually the USB port supplies 5 volt supply.
Not all do. For example on my old HP laptop there are several USB ports. One of those ports does not supply the 5 volts!.

Some devices will not work on a non powered usb computer port. This may be what you are running in to. Could also be the port may have 5 volts but not enough current required by the device the port if feeding...

[K5MBV]

YES! "Some devices will not work on a non powered usb computer port. This may be what you are running in to. Could also be the port may have 5 volts but not enough current required by the device the port if feeding..."

Maybe this is the problem. What is the solution for
a plug and play sort of person? Is there a powered hub that I could buy?

Ken  K5MBV
 
 

[AB3BO]

I would keep looking around some more but
something like this might do it.

http://www.papyrus.co.il/Products/usb_to_quad_rs-232_adapter.htm

Good Luck!

AB3BO -Don-

[KT4WO]

You might try :
Download PuppyLinux from www.w1hkj.com and run the "Live" CD and see if the com-ports work with that.
At least you will know if its windoze or hardware.

I have found that "some" hardware ports will work
under linux that wont with windoze.  and the other way around.... Just my 3 cents.

Gud Luck
KT4WO

[K5MBV]

Went and bought a powered 4 port hub. Same problem!
No port will open except for the USB to LVB Tracker box
port 16. I assigned it to port 17 and the tracker box
accepted it and worked. Then port 16 won't open!

Good Grief!

Ken  K5MBV

[K5MBV]

I bought a self powered 4 port hub and it changed nothing, so I hooked up the LVB tracker box through
the hub and it worked OK, but still can't open any
port for the CAT tuning!

Ken  K5MBV

[K5MBV]

Don, The quad rs232 box looks promising, but $141. not
in my budget just to try to see if it would work.
But thanks for the info.
Ken  K5MBV