If You insert callsign which is known in C_W database, program automatically fill up to two locators. Locators are inverse displayed. If locator on higher row is valid you must confirm it by pressing <Alt+X> key. If second WWL is valid you must swap locators by pressing <Alt+V> key. If callsign isn't contain in database, Tucnak fill a large square with highest activity or Capital City of worked DXCC and calculates aproximate QTF.
Similar situation is if you insert known locator. There'll display two inverted callsign which can swap press <Alt+C> and confirm by press <Alt+D> or shows prefixes of possible DXCC only if isn't known any callsign
Tucnak checks if pair of locator and callsign exists. If Tucnak think that it's invalid then shows at locator some of this characters.
- ! - large square doesn't lie in DXCC. If callsign and locator are correct an invalid record is in tucnakdw.
- ? - Tucnak knows locators of this station but typed locator is different
- nothing - callsign is unknown or locator corresponds with callsign.