In Alcatel you even can define Tch-Voice preferably onthe TRX with the higest possible number and Tch-Packet on the TRX with the smallest possible.
But for siemens:
We notice that data call on BCCH is not very usefull, it is better to have data only on BCCH and just to watch “intracell HO due to multislot calls”
Boko