Vtech,5.8 3-phone w/digital recorder, model

To deregister ALL handsets:
Step 1: Press and hold FIND HANDSET on the main telephone base for 10 seconds.

Step 2: When the IN USE light starts to flash, release the FIND HANDSET button.

Step 3: Press and release FIND HANDSET again. The IN USE light will turn off and in a few seconds, all handsets will be de-registered.

Step 4: All handsets will show NOT REGISTERED.

To register a handset (register 1 handset at a time):
Step 1: Place the handset in the base unit or a charger that is connected to a power outlet. If PRESS FIND HNDST 4 SEC ON BASE does not appear on the screen after a few seconds, lift up handset and place in base or charger again.

Step 2: On the telephone base, press and hold FIND HANDSET for four seconds. Release FIND HANDSET once the IN USE light comes on.

After a while the handset will emit a series of tones, the newly registered handset will be assigned the lowest extension number not previously assigned to another system handset (1-4) when successfully registered. Repeat Steps 1 and 2 if the handset does not successfully register to the telephone base within two minutes.

REPEAT THE REGISTRATION PROCEDURE FOR EACH SYSTEM HANDSET.

Make sure the handsets are not receiving interference from other appliances, cell phones, etc.

IF deregistering does not work .. you will need to reset the entire system
Step 1: Disconnect the power to the telephone base.

Step 2: Disconnect the handset battery.

Step 3: Wait a few minutes and then reconnect the power to the telephone base.

Step 4: Reconnect the handset battery

Step 5: Wait about one minute for the handset to re-establish a link with the telephone base and then test the phone again.
You will need to set the time and date again after resetting the entire system.