A method is provided of enabling a function(s) of a telephone to be controlled. The telephone is operative to perform the function(s) in response to command(s) from a printer. The method includes providing a control interface which contains information relating to the function(s) and has coded data on an identity and a reference point(s) of the control interface, receiving, in the printer, indicating data from a sensing device regarding the control interface identity and a position and/or movement of the sensing device relative thereto, and effecting, in the printer and from the indicating data, an operation(s) relating to the command(s). The coded data incorporates substantially undifferentiated marks positioned relative to a set of predetermined nominal mark positions. The sensing device, when placed in an operative position relative to the control interface, generates the indicating data using at least some of the coded data.