0x12 Vari-A-Bill

Data[0] Invoke_ID (A unique identifier that specifies
the feature request.)
Data[1] Billing Type (If the billing type is "Free call,"
you do not need to include the billing data.)
Data[2] Hundreds
Data[3] Tens
Data[4] Ones
Data[5] Tenths
Data[6] Hundredths

Bearer Capability

You must represent this field as a Raw IE. Refer to the Q.931 specification for values.

Network-specific Facilities

You must represent this field as a Raw IE. Refer to the Q.931 specification for values.

Call signaling protocol for setup and termination of calls.