When user A (3555) calls user B (3444), the attendant press *80*3444# tobreak in a call (user C whose number is 3222) to start a three-party call. However, user C hears a prompt tone indicating that the break-in fails.
Step 1 Run the config modify board slot x type mru conference yes command to set conference to yes. In the preceding command, x specifies the slot in which the MRU board is located.
Step 2 If the fault persists, contact Huawei technical support engineers.
The conference parameter of the MRU board is no.