Oki OKIFAX 5750 Service Manual page 400

3) When three digits have not been entered, the blinking cursor position moves to the next digit input by the pressing the SHIFT RIGHT key.
4) When the CLEAR key is pressed, a maximum of three characters are erased from the blinking cursor position to the dot position.
5) The ENTER key is rejected if the numeric entry space delimited by dot is empty.
6) The right-left shift key is valid during input.
7) Whether the entered value is correct is identified when numeric entry between dots is determined as shown below.
l
3-digit entry: When 3 digits are entered
l
Less than 3 digits: When the SHIFT key is pressed
8) The value that can be entered ranges from 0 to 255 but the suitable value depends on network limitation, etc.