Represents the distinctive
sound of four sets of five bell-rings. That particular arrangement indicates a firefighter has died in the line of
duty. Used especially in
New York. Similar to
Morse Code.
Used in memorial services,
funerals, and wakes; usually followed by a
moment of silence.
A bell struck in
four sets of five strikes is a
19th century New York tradition used to mark the death of a firefighter or noted community member. The ringing of four sets of five dates back to the time when firefighters used their bells to communicate over
distance.
The choice of 4 sets of 5 bells is arbitrary as far as I could find and was dated to a time where they used bells to signal all sorts of things. Arrangements of sets of rings were assigned to different notices to the public and fellow employees as the need came along, i assume.
"Upon receipt of the signal, the officer on duty shall cause display of the National Flag at half-staff at quarters (time of day being a factor) and have it remain until sunset of the day of the funeral or until such time as designated in department orders.
In the 1970s as the old bell system was being phased out the signal 5-5-5-5 began to be sent over the voice alarm and computer.
It is still the one message that causes this great department to be momentarily stilled upon receipt."
-http://ufalocal94.org/firelines/2001/fl_nov_mem_01/fl_nov_mem_01_5555history1.html
For Reference: http://www.nyfd.com/bells/bells2.html