One of the current tech advantages for sonar and GPS units is the updatable software feature. Updates can eliminate operational glitches or add new features. In the past these changes were available only when you bought a newer unit. Updates for units that have USB ports or MMC slots can usually be obtained from the manufacturer's website at little or no cost. Some sonar units without data capabilities can be updated if they are in a NEMA network or if the unit is sent in. Check with your manufacturer.
Bill Diedrich is a retired Minnetonka math teacher with a love of fishing electronics.
