Garmin GNS 480 Installation Manual page 138

Appendix B - Serial Interface Specifications
B.2.1.2 Binary Nearest List Data
The nearest waypoint lists are sent one waypoint per data transmission set. The lists are sent in the
following order:
•
LFAC
•
VOR
•
NDB
•
INT
•
User
There is a maximum of twenty waypoints per type. The waypoints are a maximum of 600 nm from the
current position. The waypoints are order by distance from current position nearest to farthest. The
maximum time to send all lists is 100 seconds. Each list is updated just prior to the first waypoint in the
list being sent. If a list is empty a shorter record will be sent with the List Item Number set to 0xFF.
Byte Format
1 Z
2 sddddddd
3 t
4 Cr
4-8 ddddd
9 sddddddd
10 xxmmmmmm
11 xhhhhhhh
12 sxxxxxxx
13 dddddddd
14 xxmmmmmm
15 xhhhhhhh
16 Cr
B.2.1.3 Flight Plan Waypoint Type Data
The following data is only transmitted when preceded by flight plan data. There is one character per
flight plan waypoint transmitted.
B-10
Table B- 8 - Nearest Waypoint List Data
Description
'Z' Item Designator
List Item Number: Packed, unsigned binary values
s = 1 End of list, 0 all other
ddddddd = 1 – 20 list waypoint index
sddddddd = 0xFF List Type is EMPTY (BYTE 4 terminate Item)
Waypoint Type:
t = {a (airport) || v (VOR) || n (NDB) || i (INT) || u (USER)}
'\r' Item Terminator <0x0d> (ONLY IF BYTE 2 = OxFF)
ASCII Waypoint Identifier
Latitude of waypoint. Packed, unsigned binary values for degrees, minutes
and hundredths of minutes.
s = 0 North latitude, 1 South latitude
x = undefined
ddddddd = Latitude degrees
mmmmmm = Latitude minutes
hhhhhhh = Latitude hundredths of minutes
Longitude of waypoint. Packed, unsigned binary values for degrees, minutes
and hundredths of minutes.
s = 0 East longitude, 1 West longitude
x = undefined
ddddddd = Longitude degrees
mmmmmm = Longitude minutes
hhhhhhh = Longitude hundredths of minutes
'\r' Item Terminator <0x0d>
560-0982-01 Rev A GNS 480 (CNX80) Installation Manual