Wulfsberg Electronics Division CVC-151 用户手册

 

Publication No. 150-047012 

Page 31 

Rev. D 

Dec 2005 

 

The SD-442 has only three controls. Each is a 
momentary, spring-loaded type that releases when 
finger pressure is removed.  On-off power is through 
an external switch such as a radio or avionics 
master switch, or a dedicated DME switch.  Volume 
control of DME station identification audio is also 
external, typically located on an audio panel. 

 

NAV -   Alternately places annunciator 1, 2, or RNV 

in display. 

1    -  

Selects NAV System 1 as the controller of 
the DME channel. 

2    -  

Selects NAV System 2 as the controller of 
the DME channel. 

RNV -  Allows the SD-442 Selector Display to be 

used as a "repeater" display or 
RNAV-computed distance to a waypoint 
and ground speed.  This allows RNAV 
data to be available during times it might 
not be displayed by the RNAV System (for 
example, when other data is selected for 
display on some types of RNAV's). 

 

HOLD - Pressing and releasing this switch does the 
following: 

A. 

Locks the appropriate channel of the DME 
frequency in use.  Aircraft wiring will affect 
the way in which the hold feature works. In 
some installations, pin 58 ground, the hold 
switch will only place the corresponding 
channel in hold.  In others, pin 58 open, the 
hold switch will place the displayed channel 
into hold. 

B. 

Displays the current NAV frequency that 
determines the DME channel. 

C.  Disconnects control of the DME from the 

NAV Receiver. 

D.  Displays annunciation HLD. 

 

The purpose of this switch is to allow the 
NAV Receiver to be set to other frequencies 
without affecting DME operations.  The DME 
continues to function on its "holding" channel. 

 

Pressing and releasing this switch while in 
the HLD mode will return control back to the 
indicated NAV System (1 or 2).