Garmin GNC 255 Installation Manual - page 90
GTR 225/GNC 255 TSO Installation Manual
190-01182-02
Page B-10
Rev. B
Example message:
$PGRMV27E40
This example command would set the active VOR frequency to 117.100MHz. This can be interpreted by
noting that the ASCII ‘E’ corresponds with 45h, +30h = 75h, converted to decimal equals 117 for the MHz
portion of the command. The KHz portion converts ASCII ‘4’ to 34h, -30h = 4h, x 25KHz steps =
100KHz.
Note: The GNC will check input frequencies for validity. An RS-232 serial error message output will be
generated if the frequency is invalid.
B.2.4.1.8 Set Standby NAV Frequency
This message is used to set the standby NAV
Message format:
“V” ..........................Message class. This is a GNC NAV message.
“28”.........................Message identifier.
mk ...........................Standby VOR/LOC frequency:
m = desired frequency in MHz in hexadecimal, where m = desired frequency - 30h, with desired
frequency in range of 108 to 117MHz.
k = desired frequency in KHz, where k = (desired frequency / 25KHz) + 30h, with desired
frequency in range of 000 to 975KHz in 50KHz steps, or the even numbers
from 30h to 56h.
“0”...........................Reserved, data in this field will be ignored.
Example message:
$PGRMV28?P0
This example command would set the standby VOR frequency to 111.800MHz. This is interpreted by
noting that the ASCII ‘?’ corresponds with 3Fh, +30h = 6Fh, converted to decimal equals 111 for the MHz
portion. The KHz portion converts ASCII ‘P’ to 50h, -30h yields 20h, x 25KHz steps = 800KHz.
Note: The GNC will check input frequencies for validity. An RS-232 serial error message output will be
generated if the frequency is invalid.