Power-Up Check
Plug in any PA-KP local power supplies that are being used, and also turn on any system power supplies that are being used. When power is first applied to the US2002, it will perform a power-up reset, in which the front panel indicators will cycle through all of their possible colors and then turn off. This verifies the general operation of the intercom station and indicators. The US2002 also reads the settings of all DIP switches at this time and configures itself accordingly.
Test Tone
The US2002 can generate a test tone, which can be used to verify intercom channel operation after installation or to locate a malfunction. This test tone is also used for the sidetone adjustment which follows. Use the test tone as follows:
1.Simultaneously press the All Talk and PA keys to activate the test tone.
2.Tap the Call key for the channel that you want to test (can be either a US2002 channel or an ES4000A channel).
3.Verify that the test tone can be heard at all intercom stations on the channel. Replace any defective cable or intercom station where the test tone is being lost.
4.Tap the same Call key to stop the test signal on that channel.
5.Press any key except a Call key to turn off the test tone.
Sidetone Adjustment
The US2002 uses full-duplex audio (the same as a conventional telephone line) in which the talk and listen audio are sent and received on the same line. Thus, when you talk on a channel, you will also here your own voice back in the speaker or headphones. This is called sidetone. If you are using the US2002 with a microphone and speaker, sidetone could cause unwanted feedback, since the micro- phone may pick up your returned voice audio and re-amplify it. This could also happen if you are using a headset where the ear cushions do not completely cover the ears, although it is probably much less likely. In either of these cases, you should minimize the amount of sidetone. On the other hand, if you are using headphones that completely enclose the ears, a certain amount of your own voice level is desirable to overcome the muffled sensation when talking.
If you are using a speaker and microphone, or open-ear style headphones, adjust sidetone as follows:
1.Simultaneously press the All Talk and PA keys to activate the test tone.
2.Tap the channel 1 Call key to send the test tone on channel 1.
3.Increase the volume until you can hear the test tone. (If you are using a headset, adjust the volume control at the US2002. If you are using a speaker, adjust the volume control at the speaker).
4.Using a small flat-bladed screwdriver, adjust the channel 1 sidetone through the access hole in the bottom of the US2002 (Figure 16) to minimize the tone volume.
5.Tap the channel 1 Call key to turn off the test tone on channel 1 when finished.
6.Tap the channel 2 Call key, and repeat the adjustment for the channel 2 sidetone.
7.Tap any other key, except a Call key, to turn off the test tone when finished.
