Each SP trunk can have a different ring pattern. The ring pattern is determined by a Ring Profile and a Ring Pattern Number. These can be found here:
Voice Services -> SPx Service -> X_RingProfile
Voice Services -> SPx Service -> X_DefaultRing
The Ring Profiles are found here:
Ring Settings -> Ring Profile A/B
Ring Pattern 1 is a single ring.
Ring Pattern 3 is a double ring.
This is the default Ring Pattern 3:
60;(.8+.4,.8+4)
60 = 60 seconds
.8 = ring for .8 seconds
+.4 = silence for .4 seconds
.8 = ring for .8 seconds
+4 = silence for 4 seconds
Repeat for a total of 60 seconds
These ring patterns can be modified.
Use OBi Expert to change these parms.
Here is the Admin Guide:
http://www.obihai.com/docs/OBiDeviceAdminGuide.pdf