To reset the memory of your 220XLT, hold down '2', '9' and 'MANUAL' while powering ON, this will clear all frequencies.
Here is also another trick...
To view the battery voltage, The 'DATA' and 'MANUAL' keys are held down while powering on the radio. This will display a number somewhere between 1.4 and 1.7
1.4 means the battery pack is nearly empty and 1.7 indicates a full charge.
This is a great feature for determining whether the pack is full or nearly empty.
It also works for the BC-120XLT scanner.
Hope this helps...