1 2 3 4 5 (annunciators)
HP48 onlyThe HP48 indicates the states of user flags 1 through 5 in the status area with little annunciators in font size 1. To turn them off, clear the respective flag(s), e.g. 1 CF makes the '1' annunciator go away.
The most frequently asked question from an HP48 newbie is, “What does the little '1' at the top of my display mean?” It means that he didn't Read The Fine Manual.
Factoid: The HP48 was designed with these flag annunciators to make previous HP-41 owners happy, since they often used its flag annunciators in the same way that mainframe programmers of olden times used the “front panel” lights to indicate various information. (The HP-41 also has annunciators for its first five flags). By time the HP49G was designed, however, it was decided to eliminate the user flag annunciators, since they were obsoleted by robust programmable user interfaces that were far easier to use and understand.
See also: SF CF