How do I clean up COM ports in use?

http://superuser.com/questions/408976/how-do-i-clean-up-com-ports-in-use

1. Click start → Run → type regedit and click OK button

2. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\COM Name Arbiter

3. Now on the right panel, you can see the key ComDB. Right-click it and click modify

4. In value Data section select all and delete reset to zero (0)

Its 32 bytes with 8 bits in each byte in hexadecimal representation. A bit of value 1 makes a port number (1...256) reserved. The first 8 ports are in the first two hexadecimal values, the next 8 ports are in the second and so on: hex F3 24 would be binary 1111 0011 0010 0100, which means that following ports are used: 1, 2, 5, 6, 7, 8, 10, 15 enter image description here

5. Close the registry editor and then restart your computer. If you set the value to 0 all COM ports are free.

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요약

1.  장치관리자 실행
2.  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\COM Name Arbiter 찾아감
3.  ComDB를 수정하여 모든 값을 00으로 만들면 됨 (1로 표시된 bit가 사용중인 것)