Invalid serial port name

I use a spider with a T35 LCD display and the USBclientDP.

On the schematics I can see

COM0 on X11 connector
COM1 on X4 connector
COM2 on X8 connector
COM3 on X9 connector

On the software (VS2010)
The availables comport are COM1 to COM4

UART = new SerialPort(COMx, Speed);

Is the COM1 software correspond to COM0 on the hardware and so on ?

Microsoft.SPOT.Hardware.dll version 4.1.2821.0
Gadgeteer version 2.41.0
Runtime version 4.0.30319

I don’t see ‘COM’ term on the schematics but ‘RX’ and ‘TX’ instead. The number i related to UART number which is not always translated to the same COM number. Usually though its +1 rule so UART0 becomes COM1 in .NET. But this is not always true so i always do a loopback test to know i got the correct port (wire RX and TX together, send data and wait for receiving it back).

In the past, with the FEZ Cobra, the TX/RX number was corresponding to COM.

Effectively, for me COM0 correspond to TX0/RX0 etc…
But If it’s a .NET rule… it’s ok for me

I think this is originaly Windows rule that COM ports are enumerated from 1…

Yes you’re right.
Thanks for the help !