When using the CELL_FACH you can choose the :
data type of the
(Main All & User)
time interval between the last preamble and the first DPCCH ( – Range: 18944 to 26348)
Number of Preamble (Range: 1 to 1022)
, , and (n Frames – Range: 1 to 1022)
(Range: 0 to 16777215)
...
For more, refer to Uplink Channel Setup - Advanced.