the display shows EST SEC when the security code must be reset.
1. place the handset in the base station cradle.
2.press INT/TRAMS/PAGE on the base station (within 8 seconds)
a beep sounds, andthe channel number in use appears in the display to confirm the completion of security code setting.
if you experience difficulty in resetting secrity code.first disconnect the AC adaptor from the unit, reconnect it, and then try again.
I hope it ganna works.
Dickember Mc, August 2008