Nominal,
A flasher is a type of sonar unit that displays the sonar returns instantly without having to process the signal and display it in graph format. Before LCD displays (about 15-20 years ago), the flasher and paper graph was about the only thing available to be used in bass boats. BTW, there still is nothing made today that will display the resolution of the old Lowrance X-16 paper graph. 1000 lines of resolution!
The advantage of the flasher is that the sonar return is displayed instantly and in real time. Using a a LCD chart recorder you are well past the spot by the time the information is displayed on your screen.
Much more information than depth is available to a skilled flasher user. You can determine bottom composition, see fish, and much more. Like any other piece of equipment the longer you use, it the more skill you develope.
The Lowrance 1240A uses a flashing neon tube for the display, and is highly visable both day and night. The Zercom (now Hummingbird) uses a LCD display.
In my opinion, the Lowarance 1240A is by far the superior unit. Yes, I've used both.
Here are some links for more information:
http://www.basspro-shops.com/servlet/catalog.TextId?hvarTextId=16059&hvarDept=200&hvarEvent=&hvarClassCode=1&hvarSubCode=1&hvarTarget=browse
http://www.marine-outboards.com/marine-electronics/zercom/zercom-classic-in-dash-flasher.htm
Russ
