Telex MCE325 用户手册
4-12
C S I - 2 0 0 U s e r I n s t r u c t i o n s
ISO Test
1
Set DIP switch DS3 to off (two-channel, two-wire mode).
2
Set DIP switch DS5 to on (talk muted during ISO).
3
Set all TALK and LISTEN buttons to on.
4
Connect a 100 ohm resistor from the ISO input (J22 pin 12) to circuit common (J22 pin 10).
Observe that the MIC ON LED turns on and the channel 1 and 2 TALK buttons turn off.
Observe that the MIC ON LED turns on and the channel 1 and 2 TALK buttons turn off.
5
Remove the 100 ohm resistor across the ISO input.
6
Reset DIP switch DS3 to on and DS5 to off.
Remote Mic Switch Test
1
Set all buttons to off.
2
Connect a 100 ohm resistor from the remote mic switch input (J22 pin 25) to circuit common
(J22 pin 10), and observe that the MIC ON LED turns on.
(J22 pin 10), and observe that the MIC ON LED turns on.
3
Remove the 100 ohm resistor.
Program Lockout Test
1
Set DIP switch DS4 to on (front panel setup lockout enabled).
2
Press and hold the CALL button for ten seconds, and verify that the MCE325 does not enter
program mode.
program mode.
3
Reset DS4 to off.
Noise Checks
1
Connect a 150 ohm load across the dynamic mic input (J2 pins 1 and 2).
2
Connect an 8 ohm load across the speaker output.
3
Connect 51 ohm loads across the left headphone output (J2 pins 3 & 4) and right headphone
output (J2 pins 3 &5).
output (J2 pins 3 &5).
4
Terminate each intercom channel into 200 ohms.
5
Set the MIC ON button to on.
6
Set the SPKR ON button to on.
7
Set all other front panel buttons to off.
8
Set all volume controls to minimum.
Note: Noise measurements in the following steps were made using a 30 kHz low pass filter
with +20 dB of gain inserted between the AC voltmeter and the MCE325.
with +20 dB of gain inserted between the AC voltmeter and the MCE325.
9
Set the CH 1-3 volume control to maximum. Measure noise across the left headphone output. It
should measure -44 dBu or less.
should measure -44 dBu or less.
10
Set the CH 1-3 volume control to minimum and set the CH 2-4 volume control to maximum.
Measure noise across the right headphone output. It should measure –44 dBu or less.
Measure noise across the right headphone output. It should measure –44 dBu or less.
11
Set the CH 2-4 volume control to minimum. Measure noise across the speaker output. The
meter should read –44 dBu or less.
meter should read –44 dBu or less.