Input devices are specified as the components of a bit mask, as described in Input Devices of a Device Group. You select one or more of the input values owned by your Device Group in a procedure body.
From the Body editing menu select the Procedure overview. When you are prompted for Input subdevice you may enter a value specifying your input device(s). Pressing Ctrl+P will generate a list of the available input devices that belong to your Device Group.
Procedures used to access the DP4 Till would normally select input device 1 at this point (the keyboard). However, some procedures may expect input from the scanner. These procedures would select the value 2, as shown in the following figure.
Note that it is possible to select multiple input sources. For example, 3 specifies keyboard and scanner. Note that the keyboard is normally defined as input device 0. It only needs to be defined as some other value if you wish to combine input from other sources.