This chapter contains a variety of topics, in no particular order. This information is not required for basic 1090 operation but it is helpful for better understanding the 1090 and for more advanced uses.
1.1 Token dates and times
The 1090 and 1091 tokens remember the latest date and time that it sees from the underlying Linux system. It uses the Linux “software clock” for this purpose, without any time zone adjustment. The token must never see the date or time move backwards. If this happens, a time cheat message is produced and ...