5.18.3.3.2. Generation Notes on A Station Identification (After the B Number) 
In this method, the A number is only retrieved if the reached station
is correctly administered. The advantage is that calls do not use the
SIU MFC devices longer than necessary. The disadvantage is that the time
between "preliminary seizure" and ringing is considerably longer. If
the B station picks up during this time, the call is signaled to the
central office with "FREE" but the busy tone is applied.
To make sure that the A station number is retrieved from the central
office, perform the following generations with COT, COSSU, and FEASU:
Identification without allowing the tracing expression:
- COSSU: Station COS with TSUID for retrieval of the A number when there is a call to the station.
- COT: ATDI for retrieval of the A number when there is a call to the AC (call queue).
- COT: TIEI for retrieval of the A number when there is a call via DAR TIE.
- FEASU: TRACCO = YES
Identification while allowing the tracing expression:
- COSSU: Station COS with TSUID and FANGAUT (if there is automatic tracing)
- FEASU: TRACCO = YES
- WABE: Digital analysis result TRACE (for manual tracing)