PURPOSE: To indicate data in the form capable of setting readily and not requiring any understanding of an operator by putting icons on a bus line that indicate symbolically events created within an optical cable to be tested.

CONSTITUTION: On a bus line 42 indicated over the entirety of an indication portion 40, icons 44, 46, 48, 50, 52 are put for symbolically indicating events created within an optical cable to be tested. Also, the maximum length of a cursor 54 indicated 40 is equal to the length of the base line 42. A distance indication area 56 by alphameric characters indicates the length of the cable from the front end of the cable to a specific icon indicated by the cursor 54. Provided under the base line 42, cursor 54 and area 56 is a second alphameric character area 58 showing kinds of events designated by the cursor 54 and losses of signals. As such, data can be indicated in the form capable of setting easily and not requiring any understanding by the operator.