MCU convenes IAD to conference call, and the IAD phone rings but interrupts when hold it. It is normal to convene video terminal to conference.
When adding conference sites in MCU, the conference type of video terminal is:
IP transmission rate: 768Kbit/s (default)
When adding IAD phones, conference site type is:
PSTN transmission rate: 64Kbit/s
Data configuration problem
This problem causes by selecting conference site type and transmission rate to default value.