Installation manual

Serial Interface Specifications

Apollo SL30 Installation Manual

Example message:

$PMRRV28?PM<chksm><CR><LF>

This example command would set the standby VOR frequency to 111.800 MHz. This is

interpreted by noting that the ASCII ‘?’ corresponds with 3Fh, +30h = 7Bh, converted to decimal

equals 111 for the MHz portion. The kHz portion converts ASCII ‘P’ to 50h, -30h yields 20h,

x25 kHz steps = 800 kHz. This command would also set the receiver function to monitor, so the

receiver would time-multiplex the active and standby VOR channels to track both stations.

Note: The SL30 will check input frequencies for validity. An RS-232 serial error message output

will be generated if the frequency is invalid.

SET STANDBY COMM FREQUENCY

This message is used to set the standby COMM frequency.

Message format:

“V”................ Message class. This is a VHF NAV message.

“29”............... Message identifier.

mk ................. Standby COMM frequency:

m = desired frequency in MHz in hexadecimal, where m = desired

frequency - 30h, with desired frequency in range of 118 to 136 MHz, or

162 MHz.

k = desired frequency in kHz, where k = (desired frequency / 25 kHz) +

30h, with desired frequency in range of 000 to 975 kHz in 25 kHz steps.

Example message:

$PMRRV29G4<chksm><CR><LF>

This example command would set the standby VOR frequency to 119.100 MHz. 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, x25

kHz steps = 100 kHz.

Note: The SL30 will check input frequencies for validity. An RS-232 serial error message output

will be generated if the frequency is invalid.