Lesson 1/Learning Event 4
(d) The TEST TONE jacks provide a test tone (1004 Hz) at the proper
level for the facility where it is used.
(e) The SPEAKER (SPKR) jacks provide a means of monitoring audio signals
such as voice, test tones, signaling frequencies, etc.
(f) Above each jack of the miscellaneous module is a light that comes on
any time a plug is inserted in the jack. The lights are important because
the test tone jacks, speaker jacks and meter jacks are connected to more
jack is in use.