EFJohnson VR-CM50 manual CPP Adjustments, Console Adjustments

EQUIPMENT CHECK-OUT AND ADJUSTMENTS

7.Observe the LEDs on the channel modules. On module-based consoles, each channel module should have either the yellow or green LED adja- cent to the volume control on.

Touch the volume control cap on individual chan- nel modules. The LEDs should toggle smoothly between yellow and green, with no delay as the cap is touched.

In normal operation, auxiliary switch and paging modules may show no indications until the function is actually used. Think before you press buttons! You could interfere with other operations or accidentally set off pagers and sirens.

8.If at this point, the CPP and all console positions appear to be performing normally, proceed ahead to level setting and point by point testing.

NOTE: The system should be allowed to "burn-in" for a minimum of 72 hours, before being placed into actual service, to allow any possible "infant mor- tality" problems to surface and be resolved.

6.2 CPP ADJUSTMENTS

The only level to be adjusted in the CPP is the Tx Output from each Line Interface Controller. Rx lev- els are automatically adjusted under processor con- trol. The initial Tx and Rx level settings are factory adjusted and programmed in accordance with the data furnished to E.F. Johnson at the time of order. Tx lev- els should be set using industry standard techniques for 600W balanced line audio.

NOTES:

The receive input for each channel will be pro- grammed for either 2 wire or 4 wire audio input in accordance with the data furnished at the time of order. The 2 wire receive audio path is disabled on any channel specified by the customer as having a 4 wire interface.

All DC controlled channels are shipped with the DC current generator appliqu board disconnected to pre- vent accidental electric shock injury to the installer. These appliqu s must be plugged in prior to testing any DC controlled channels.

The Tx and Rx levels between the CPP and the Console are fixed and cannot be adjusted. The nomi- nal level is 0 dBm across 600W. If the console is being operated through a Remote Interface Adapter (RIA), level adjustment is automatically maintained through ALC amplifiers.

6.3 CONSOLE ADJUSTMENTS

There are several control adjustments that can be made to optimize the performance of the console. These adjustments are located on the right side of the control tray when viewed from the front of the con- sole.

Panel Microphone

The sensitivity of the panel (or primary) micro- phone is adjusted by the MIC 1 control, R11. This control should be adjusted to just below the knee of compression for a typical operator speaking in a nor- mal voice at the normal working distance from the microphone. If set too high, the mobile units will complain about excessive background noise and a "barrel" quality to the dispatcher’s voice. This is caused by excessive compressor action on the control tray.

NOTE: The MIC 1 and MIC 2 controls are SENSITIV- ITY adjustments, not OUTPUT adjustments. The audio level from the tray is fixed and cannot be increased through the use of these controls.

Auxiliary Microphone

If the console is equipped with an Auxiliary (or secondary) microphone, such as a desk microphone at an NCIC terminal, it’s sensitivity can be adjusted by the MIC 2 control, R16. See the paragraph above for details.

Headset Transmit

The transmit sensitivity of the headset lipmicro- phone is adjusted by the HS control, R6. Note that many amplified headsets have an internal compressor as part of the headset mic circuitry. Be sure the con- sole HS control is set just below the knee of compres- sion to avoid double or constant compression.

February 1996
Part No. 004-3039-274	6-2