Touch device detection

A method for detecting the presence of a pointing device 117 at an interactive surface 10, with the interactive surface provided with an illumination field for detecting a contact point, comprises: identifying a contact point 117a using the illumination field 113, 115; exciting any device proximate the field utilising the illumination field; determining if a wireless signal 118 is received from a device excited by the illumination field; and in dependence on receipt of a wireless signal identifying data associated with the contact point as touch data and/or pen data. A method for a pointing device of an interactive display system comprises detecting receipt of a coded signal and transmitting confirmation of the detection. A contact detection system comprises bezel apparatus 110, 112 for identifying a contact point on a surface, wireless detection circuitry, and identification circuitry. The pointing device may be a pen or stylus. The bezel emitters 110, 112 may use infrared emissions. The interactive surface may be an interactive whiteboard. An interrogation signal 116 may be transmitted to a pen on a back channel.