English to Japanese Tech/Engineering Medical: Instruments maintenance instrument

Electrical Safety Test

a. Plug the Nuerodyne-Dempsey 431F electrical safety analyzer into a grounded outlet. Check line voltage by switching the FUNCTION knob on the unit to LINE. The meter will indicate the line voltage. Verify that it is within the boundaries shown by the LINE square on the meter scale. Perform a CAL-CHECK by switching the FUNCTION knob on the unit to CAL CHECK. The meter should indicate within the boundaries of the CAL square on the meter scale.
上記文中の｢LINE square｣および｢CAL square｣の訳をどうすれがよいかわかりません。アドバイスをお願い致します。