完成A接口倒换后,BSC出现2992错误(BTS AND TC UNSYNCHRONIZATION CLEAR CALLS ON A INTERFACE alarm),说明A接口可能存在哪类问题()
A interface exist crossconnect circuit
B. inconsistent CCSPCM between BSC and MSC
C. A interface exist loop circuit
D. inconsistent circuit number in circuit group between BSC and MSC