Telex MCE325 manual Panel Mic/Headset Mic Selection, Microphone On/Off, Speaker On/Off

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button action can be changed, via the front panel programming, so that the button controls talk only, with listen either always on or always off.

Panel Mic/Headset Mic Selection

The PANEL MIC button selects either panel microphone (LED on) or headset microphone (LED off).

Microphone On/Off

The MIC ON button turns the microphone on (LED on) or off (LED off).

NOTE The MCE325 can be programmed, via the front panel, so that the microphone will automatically turn on whenever a channel is activated for talk. The MCE325 may also be internally programmed for voice-activated microphone (VOX) as previously described in Section 2.

Speaker On/Off

The SPKR ON button turns the external speaker on (LED on) or off (LED off).

Volume Adjustment

Table 3.1 summarizes the operation of the volume controls for the various intercom line configurations. The MCE325 is pre-programmed for stereo operation; CH 1 (VOL 1) adjusts the level to the left headphone and CH 2 (VOL 2) adjusts the level to the right.

NOTE The MCE325 can be programmed, via the front panel, for monaural operation if desired.

The PGM VOL control adjusts the monaural mix of both program inputs to both headphones and to the external speaker. It does not affect the program volume on the intercom lines.

Front Panel Sidetone Nulling Trimmer Adjustment

When the MCE325 is used with two-wire lines, the station operator’s voice signal is not only transmitted onto the intercom lines, but also echoed back into the MCE325 receive circuits. This can result in acoustic feedback when the MCE325 is used with an external speaker. The sidetone nulling trimmers are used to null, or subtract, the station operator’s voice signal from the rest of the received signal to prevent this feedback. (NOTE: This is not necessary in four-wire systems since transmit and receive use separate circuits.) A trimmer is provided for each of the four channels. The trimmers are factory-preset for maximum nulling of the microphone signal when an ideal 200-ohm resistance terminates each intercom channel; however, the trimmers may require slight readjustment after the MCE325 has been installed to compensate for variations from the ideal.

To adjust the sidetone nulling trimmers:

1Turn the speaker switch on (even if an external speaker is not connected). This will turn off the internal, true sidetone trimmer (see note below).

2Turn on the microphone.

3Activate one talk button at a time, and speak into the microphone. Slowly increase the volume, and note the level of your voice in the headphones or speaker. Adjust the corresponding sidetone nulling trimmer to minimize your voice signal. Repeat for each channel being used, making sure that only one channel is activated at a time.

NOTE There is also an internal, true sidetone trimmer, which allows the station operator to hear his or her voice when using headphones. This sidetone signal is turned off when the speaker switch is

3-2C S I - 2 0 0 U s e r I n s t r u c t i o n s

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Contents Model MCE325 Proprietary Notice Return Shipping Instructions End-User License Agreement for Telex Software Table of Contents Operation Diagrams Page Description FeaturesGeneral Front Panel Features Connections, Inputs and OutputsRear Panel Features Intercom LinesMounting Configuration PowerProgramming Microphone Preamplifier MCE325 SpecificationsPower and Mechanical Headphone AmplifierMCS325 Specifications ConnectorsStandard four-channel, two-wire configuration Standard two-channel, four wire configuration Page 10M C E 3 2 5 U s e r I n s t r u c t i o n s 11 MCE325 button configurations 12M C E 3 2 5 U s e r I n s t r u c t i o n s Installation Internal Programming and AdjustmentsSwitch Number Switch Function Default Setting Jumper Number Jumper Function Default Setting Internal DIP switches, jumpers and level trimmers Front Panel Setup Mode Lock-out DS4 Remote Talk-off DS7Speaker Dim Adjustment R157 Mechanical InstallationHeadphone Sidetone Trimmer Adjustment R37 Program Assignment IFB Option J4, J5, J16-J18Mounting configurations AC Power and Fuse Electrical InstallationIntercom Lines J8, J9, and J10 Program Inputs, J14 and J15 Auxiliary Connector, J22Four-Wire Channel a and B Input External Speaker, J27ISO Connection Remote Microphone SwitchKey outputs Expanded IFB Option External HeadsetFront Panel Headset Connections Carbon-microphone headset connector Operating Instructions LED IndicatorsGeneral Momentary/Latching Button actionPanel Mic/Headset Mic Selection Volume AdjustmentFront Panel Sidetone Nulling Trimmer Adjustment Microphone On/OffFront Panel Programming Channel ID Call DisableLatch Disable Four-channel ListenReset Instant Mic6C S I 2 0 0 U s e r I n s t r u c t i o n s Access Preventive MaintenanceCorrective Maintenance Factory Support InformationPower Supply Test Test and Adjustment ProceduresCleaning Test EquipmentInitial Configuration Keying Output TestFour-Channel, Two-Wire Mode Frequency Response and Level Check, Mic to LineSidetone Null Test and Adjustment Two-Channel, Four-Wire ModeTrue Sidetone Adjust Talk Button Test Point PotentiometerProgram a to Left Headphone Program B to Right Headphone IFB TestProgram to Speaker Four-Wire a Input to Left Headphone Four-Wire B input to Right HeadphoneVOX Test Panel Mic to Channel TestCarbon Mic to Channel Test Mic Kill Receive TestCall Transmit Test Mic Kill Transmit TestCall Receive Test Program Lockout Test Remote Mic Switch TestISO Test Noise ChecksPage 14C S I 2 0 0 U s e r I n s t r u c t i o n s Packaging Assembly Final Assembly, MCE325Front Panel Assembly Heatsink Assembly Back Panel AssemblyMain PC Board Assembly 4C S I 2 0 0 U s e r I n s t r u c t i o n s Reference 9027-6245-01 Drawing, Section CR1 FB1 #73 Shield Bead 8C S I 2 0 0 U s e r I n s t r u c t i o n s Reference 9027-6245-01 Drawing, Section 10C S I 2 0 0 U s e r I n s t r u c t i o n s RP2 Washer Flat PC Board Assembly, Front Panel DS1-DS814C S I 2 0 0 U s e r I n s t r u c t i o n s Diagrams 2C S I 2 0 0 U s e r I n s t r u c t i o n s Date 7/23/01 Title D\TEMP\AS624501D.cal Title D\TEMP\AS626101C.cal Title D\TEMP\AS626201C.cal Date 7/19/01 Title D\TEMP\AS646401G.dwg Title D\TEMP\BD646401A.cal Title D\TEMP\IS671801A.cal Title D\TEMP\OD635501A.cal Title D\TEMP\OD635502A.cal Title D\TEMP\OD635503A.cal Title D\TEMP\OD635504A.cal Title c\home\cms\benedil\view\9000-646401.CAL Telex Mother Board Mother Board MCE325 Title D\TEMP\SD624601A.cal

MCE325 specifications

The Telex MCE325 is a sophisticated communications headset designed primarily for professionals who demand clarity and reliability in their audio equipment. Renowned for its advanced features and high-quality construction, the MCE325 is a popular choice in various fields, including aviation, broadcast, and live event production.

One of the standout features of the Telex MCE325 is its superior noise-cancellation technology. This headset is engineered to effectively reduce ambient noise, allowing users to focus on important audio signals without distractions. The exceptional passive noise isolation works in tandem with the active noise-cancelling capabilities to ensure that you can communicate clearly, even in loud environments.

The MCE325 also incorporates a high-performance microphone that delivers crystal-clear sound transmission. The flexible boom design allows users to position the microphone for optimal voice pickup, making it suitable for both left- and right-handed users. The microphone’s windscreen further minimizes wind noise, providing an extra layer of clarity during outdoor use.

Comfort is a critical aspect of the MCE325. The headset features plush, padded ear cups that provide excellent comfort for extended use. The adjustable headband ensures a secure fit, catering to a wide range of head sizes and shapes. This ergonomic design minimizes fatigue, allowing users to maintain focus during long hours of operation.

Connectivity is another area where the Telex MCE325 excels. It is versatile enough to work with various devices, thanks to its dual 1/4” and XLR connectors. This flexibility makes it compatible with many audio interfaces and communication systems used in professional settings. The headset also includes a detachable cable, allowing for easy replacement if needed.

The construction of the Telex MCE325 reflects a commitment to durability and longevity. Built with high-quality materials, the headset can withstand the rigors of demanding professional environments. This robustness ensures that users can trust the MCE325 in the most challenging situations, whether it’s in a busy studio or a bustling airport.

In summary, the Telex MCE325 is a versatile and reliable headset designed to meet the needs of professionals across various industries. With its cutting-edge noise-cancellation technology, high-quality microphone, comfort-focused design, versatile connectivity options, and durable construction, it stands out as an ideal choice for anyone seeking superior audio performance and reliability. Whether in communications, aviation, or live broadcasting, the MCE325 delivers an exceptional audio experience.
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