Operator`s manual
V A L   A V I O N I C S   L T D  
N A V   2 0 0 0     N A V I G A T I O N   S Y S T E M  
I N S T A L L A T I O N   A N D   O P E R A T O R ’ S   M A N U A L  
Pre-Release Issue                Page 22 of 29 
Sept. 2013 
8.6  Message Definitions 
Input Messages 
REQUEST DATA OUTPUT 
This input is used to request an output message to be sent by the NAV 200. 
Message format: 
 “V” ...............................Message class. This is a VHF NAV message. 
 “24” ..............................Message identifier. 
ii ....................................Output identifier of requested message, two ASCII characters. 
dd...................................Message data, two encoded hex
2
 characters (30h-3Fh), used for specific 
output request. Set to “00” if not needed. These characters are used for 
such items as selecting a specific EEPROM address to output. 
A....................................Request type: (ASCII) “0”= output repeatedly at low speed (1 Hz); “H” = 
output repeatedly at high speed (10 Hz). 
ii  Output  Dd  Data Description  a 
“20”  Reset Status  “00” 
“0” 
“21”  CDI, GSI, and Flags  “00” 
“0”, “L”, “H” 
“22”  Decoded OBS Setting  “00” 
“0”, “L”, “H” 
“23”  Radial from Active VOR  “00” 
“0”, “L” 
“28”  Receiver Status  “00” 
“0” 
“30”  NAV Microntroller Software Version  “00” 
“0” 
“32”  ADC Data Output  cc  ADC channel: “00” 
to “08” 
“0” 
“35”  Comm Transceiver Status  “00” 
“0” 
“36”  Comm Software Version  “00” 
“0” 
Table 5 - Data Output Requests 
Example messages: 
  $PMRRV242100L<chksm><CR><LF> 
Request periodic output of CDI, GSI, and related flags at low (1Hz) rate. 
  $PMRRV2432050<chksm><CR><LF> 
Request a single output of ADC data from channel 5. 
SET ACTIVE VOR/LOC FREQUENCY AND RECEIVER FUNCTION 
This message is used to set the standby VOR or Localizer frequency as well as the receiver 
operating function. The NAV 2000 can detect if the supplied frequency corresponds to a VOR or a 
Localizer channel, so this command will work for both types of NAV aids. 
2
 Encoded Hex: each character consists of 4 bits of data placed in the low order nibble +30h. For example, 
the 8-bit value of 5Fh would be encoded as two characters with values of 35h and 3Fh, which map to the 
ASCII characters “5” and “?” respectively. 










