Telex MS2002 Power Supply User Manual


 
16
Power-Up Check
Plug in the MS-2002. When power is first applied to the MS-2002, 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 MS-2002 also reads the settings of all DIP switches at this time
and configures itself accordingly.
Test Tone
The MS-2002 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 MS-2002 channel or an EMS4001
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 MS-2002 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 MS-2002 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, 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. See figure 8, page 16, for the adjustment
locations.
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.
4. Using a small flat-bladed screwdriver, adjust the channel 1 sidetone through the access hole in the bottom
of the MS-2002 (Figure ) 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.
If you are using headphones that completely enclose the ears, adjust sidetone as follows:
1. Tap the Headset key to turn the headset microphone on.
2. Tap the channel 1 Talk key to turn it on.
3. While speaking into the microphone, use a small flat-bladed screwdriver to adjust the channel 1 sidetone
so that you hear your voice at an acceptable level in the headphones. Tap the channel 1 Talk key to turn it
off when finished.
4. Tap the channel 2 Talk key to turn it on, and adjust the channel 2 sidetone as for channel 1. Tap the
channel 2. Talk key to turn it off when finished.