GAI-Tronics IPE2500A, IPE2500A-MLS Paging Encoder / Desktop Controller User and Installatoin Manual - Manual (Page 47)

IPE2500A and IPE2500A-MLS Paging Encoder/Desktop Controller Installation
41 03/12
MLS Line-Level Normalization
The most important step in proper installation of the line select option is the normalization of the line
level for each line. Normalization is necessary for the unselect audio level adjustment to function
properly. This adjustment allows the unselect audio to be heard at a lower level than the select audio so
that the operator can distinguish between the select and the unselect audio.
If not properly adjusted, the audio from one line may keep the IPE2500A compressor in compression.
When the audio causing the compression is removed, and the compressor releases, it causes the lower
audio levels to increase in perceived volume. This makes it difficult to detect the difference between
select and unselect audio. Normalize the lines as follows:
1. Measure the nominal audio level on each line before input to the multi-line select module. The
lowest measured nominal audio provides the reference level for all lines.
2. Adjust the appropriate pot (pots 1 through 4 for lines 1 through 4) to achieve unity gain through the
line-select option while measuring at the appropriate DET test point for the reference line.
3. Lower all other lines to this reference level by adjusting each corresponding pot and measuring at
each corresponding DET test point.
Making the Input Sensitivity Adjustment
Set the input sensitivity to ensure the unit’s receive audio compressor functions properly. Using the
reference level measured in Line Normalization step above, set the input sensitivity of the unit to the
closest available setting. For example, if the reference level measured was −10 dB, set the IPE2500A
input sensitivity to -9 dB. Refer to the “Level Settings and Diagnostics” section for instructions on
setting the input sensitivity.
Making the Vox Detect Level Adjustment
The vox-detect level can be adjusted using pot 5 on the Line Select board. This adjustment is set to
approximately −20 dB from the factory and normally does not need adjustment. To adjust the vox-detect
level, perform the following steps:
1. Ensure that the unit has a programmable button assigned to each of the lines being used.
2. Input a tone at the desired vox-detect level into any line after completing step 3.
3. Adjust pot 5 until the LED for the programmed button assigned to the line begins to blink. The vox-
detect level is now set.