You can specify the data point type in the following formats. Refer to the KNX specification available at http://www.knx.org
1.009 (close/open encoding)
DPST-1-9 (close/open encoding)
DPT-1 (generic boolean, no subtype)
DPST-4-1[0] (retrieves the increase/decrease encoding bit of the generic DPST-4-1 data point type, which is an 8-bit encoding)
4 or 4-xxx (generic DPST-4-xxx type)
4.001 (DPT subtype)
4.009.0 (first part of the DPST-4-9 DPT)