Hi as I seid in another posting it is not a problem to have call setup without SDCCH (direct TCH assignment in Siemens). But you need the SDCCH for the LU and SMS. But if in idle mode you never camp on this cell then there is no problem. We don’t use such thing but the idea is the following: In some countries the operators bid for 1800 the same way as for 900 so the have to have for example 97% coverage territory and 98% population on 1800. This meens that they have to have BCCH on 1800 to show coverage to the regulator. But actually they tune the cells as dualband. One site with colocated 900 and 1800.