Allows tracking of airtime usage to monitor phone expenses: Cumulative. Not resettable. Displays total time since the unit was first activated. Resettable. Like a stopwatch, timer will accumulate until the user resets it. Individual. Each call's duration can be displayed either during or after the call. Audible. Ten seconds before the end of each airtime minute, a tone is heard (Can be turned off). Automatic Display. Displays accumulated airtime during and after each call. Programmable. Programs the phone to signal: once during each call after a programmable number of seconds (one-time beep), and/or at intervals of programmable number of seconds during each call (repetitive beeps).