Defining busy patter

Hi Everyone…

I am having a lot of problems getting busy detect to work.
I found out today that the ISP that we are using is not sending the pattern that is expected based on ITU.

They are sending:
on 225 MSEC
pause 525 MSEC
on 400 MSEC
pause 350 MSEC

How do I define that as a busy pattern? As I see it I can only identify off and one, but since they differ in this place it would be something like
225,525,400,350???
Advice greatly appreciated how to handle such a signal.

Nic