Using Serial On Python / Win7

I am trying to interface with a serial WWAN modem (for diagnostics /signal strength measurement purposes). This is via the onboard COM1 (115200-8-n-1) on my desktop, the connection

Solution 1:

You don't need to call open. The constructor already does that, and on Windows whoever opens a COM port has exclusive access to it until they close it.

As to the second problem, take a look at How can I fix "[Error 6] The handle is invalid." with PySerial

Solution 2:

Here is what I do to eliminate Access Denied Error:

1. Press Ctrl + Alt + Del

2. Select pythonw.exe and press End Process

3. Re-Run your application in IDLE

It should be run without any access denied error.

Solution 3:

You need to be running python.exe in elevated mode. Right click and click Run as administrator