LMP737 From , joined Dec 1969, posts, RR: Reply 1, posted (10 years 9 months 3 weeks 6 days 13 hours ago) and read 2552 times:
The CANCEL button removes any caution or advisory messages on the upper display. The RECALL button allows you to view cautionary and advisory messages that are still applicable.
Cdfmxtech From United States of America, joined Jul 2000, 1338 posts, RR: 29 Reply 3, posted (10 years 9 months 3 weeks 6 days 11 hours ago) and read 2497 times:
He is talking about the 2 white squares mounted vertical to one another. They are located between the Stby Att Ind and the Cancel/Recall Switches.
Those are Auto Bright Sensors. They sense when cokcpit conditions are too bright and brighten the annunciator lights when they are in the dim position.