Power-Up Check
Plug in any PS-L local power supplies that are being used, and also turn on any sys-
tem power supplies that are being used. When power is first applied to the US2000A,
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 opera-
tion of the intercom station and indicators. The US2000A also reads the settings of
all DIP switches at this time and configures itself accordingly.
Test Tone
The US2000A 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 US2000A
channel or an ES4000A channel).
3.
Verify that the test tone can be heard at all intercom stations on the channel. Re-
place 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 US2000A 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 head-
phones. This is called sidetone. If you are using the US2000A with a microphone
and speaker, sidetone could cause unwanted feedback, since the microphone 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, al-
though it is probably much less likely. In either of these cases, you should minimize
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