COM driver number question


Do Windows CE and Windows Mobile has max number for COM devices ?

I have change some COM driver index from 5 to 10 or 16 , but COM10 and
COM16 can not be opened by process .

After that I change the index to 8 , then I can open COM8 by my process.

I am sure our max use number is 9, so does 9 is the max COM number that
WinCE can support ?

If I'm wrong, where can I modify the max number ?

Thank you very much