Garmin GTR 200, Installation Manual

Page: 68 / 85

GTR 200 Installation Manual 190-01553-00
Page B-4 Rev. B
Message format (GTR 225/GNC 255):
“GRM” ............ Company identifier.
“C”................... Message class.
“00” ................. Message identifier.
mk.................... Active frequency: m = MHz, where m = desired MHz frequency - 30h, ranging
from 118 to 136 MHz, (i.e. 76h to 88h, A2h); k = (KHz offset / 25KHz) + 30h,
ranging from 000 to 975KHz in 25 KHz steps.
a ....................... Transceiver function: N = normal, M = monitor, 0 = unchanged.
“0” ................... 8.33 KHz offset: (ASCII) 0 = 25 KHz frequency (.000)
Example message:
$PGRMC00G4N0<chksm><CR><LF>
This example command would set the active COM frequency to 119.100 MHz and place the radio in
Normal receive mode. This is interpreted by noting that the ASCII ‘G’ corresponds with 47h, +30h = 77h,
converted to decimal equals 119 for the MHz portion. The KHz portion converts ASCII ‘4’ to 34h, -30h
yields 4h, x25KHz steps = 100 KHz, with no 8.33 KHz channel offset.
Message format (SL 30):
“MRR” ............ Company identifier.
“V” .................. Message class.
“42” ................. Message identifier.
mk.................... Active frequency: m = MHz, where m = desired MHz frequency - 30h, ranging
from 118 to 136 MHz, (i.e. 76h to 88h, A2h); k = (KHz offset / 25KHz) + 30h,
ranging from 000 to 975KHz in 25 KHz steps.
a ....................... Transceiver function: N = normal, M = monitor, 0 = unchanged.
Example message:
$PMRRV42G4N<chksm><CR><LF>
Sets the active frequency to 119.100MHz, normal receive mode. “G” = 119d - 30h = 77h - 30h = 47h, or
an ASCII “G”; “4” = 100 kHz/25 kHz + 30h = 4 + 30h = 34h, or an ASCII “4.”
Message format (SL 40):
“GRM” ............ Company identifier.
“C”................... Message class.
“00” ................. Message identifier.
mk.................... Active frequency: m = MHz, where m = desired MHz frequency - 30h, ranging
from 118 to 136 MHz, (i.e. 76h to 88h, A2h); k = (KHz offset / 25KHz) + 30h,
ranging from 000 to 975KHz in 25 KHz steps.
a ....................... Transceiver function: N = normal, M = monitor, 0 = unchanged.
Example message:
$PMRRC00G4N<chksm><CR><LF>
Sets the active frequency to 119.100MHz, normal receive mode. “G” = 119d - 30h = 77h - 30h = 47h, or
an ASCII “G”; “4” = 100 kHz/25 kHz + 30h = 4 + 30h = 34h, or an ASCII “4.”
NOTE
Input frequencies will be checked for validity. An RS-232 serial error message output will
be generated if the frequency is invalid, or an 8.33 KHz frequency is requested.