Why is it when I plug in my Uno board it shows as com5, then when I plug in my other Uno board, it shows as com6? Is there a way to adjust this, so it is always com5?
It is not possible to have two Arduinos connected, using the same COM port.
Which COM port gets used when an Arduino is connected is a Windows thing. It depends on the PID/VID of the device and the particular USB port that is used.
PaulS:
It is not possible to have two Arduinos connected, using the same COM port.Which COM port gets used when an Arduino is connected is a Windows thing. It depends on the PID/VID of the device and the particular USB port that is used.
To clarity: when I said I plug my other Uno in, I unplug the first one and plug this one into the same USB port, and this comes up as COM6
Did you know what VID/PID means?
That just how Windows does it. If you want to be able to use the same port names for different boards then get off windows.
Hi,
I have clone UNO's that have COM as high as COM45 on my home PC and another COM on my work laptop.....
Its just the way windows does it.
Tom... 
Delta_G:
That just how Windows does it. If you want to be able to use the same port names for different boards then get off windows.
So, will Apple computers be able to use the same Com port name for different Uno boards?
What would be a recommended way to upload the same sketch to many Uno boards? What kind of equipment?
Also when I upload a sketch (that operates a GSM shield), does the GSM shield need to be attached to the Uno when uploading?
Hansen70:
So, will Apple computers be able to use the same Com port name for different Uno boards?
Interesting question.
I have an 'Apple computer' here; its a II+ Europlus.
I wonder if it understands Arduino ?
Hansen70:
So, will Apple computers be able to use the same Com port name for different Uno boards?
I don't know. I work with computers not fruit. I'm an open source guy. Apple is the Devil. Get Linux if you want to get very deep into this stuff.
Hansen70:
What would be a recommended way to upload the same sketch to many Uno boards? What kind of equipment?
What, you mean at the same time? Use an FTDI to serial converter and hook them all up to that. The FTDI adapter will have it's own com port.
Hansen70:
Also when I upload a sketch (that operates a GSM shield), does the GSM shield need to be attached to the Uno when uploading?
No.
So, will Apple computers be able to use the same Com port name for different Uno boards
Yes if they are the same Arduino type.
You can get this to upload the same sketch to many Uno boards
New addition to the CrossRoads card family: Standalone Programmers!
Standalone Programmers!
Ever needed to program some cards in the field but didn't have access to a laptop? Now you don't need one! We collaborated with Nick Gammon and turned his "Upload Hexfile from SD card" into a full-fledged standalone programmer. Connect up a power source (3xAA battery pack, 5VDC wallwart, 7-12VDC wallwart or non-running vehicle power), select a program and press the Start button. More details on this page for file naming and re-setting up the card if needed.
Programming an Uno under battery power. Select from 1 of 256 files via the rotary encoder:
