To deregister the new handsets from their old bases and re-register
them to your base, try this for each new handset...
1. When the new handset says "Connecting..." and goes nowhere
else, enter *331734 [menu] and it will soon beep and display
2. To register the new handset to your base: on the base press
the "Handset Locator" button and hold it until the "in use" light
comes on ( ~ 4 seconds ), then release the button and set the
new handset into the base phone cradle. After ~ 30 seconds
it will beep and display its "Handset #" (next in sequence).
3: Note: the base has a limit to how many handsets it can handle,
I believe it is five handsets maximum for the EL52300.
If your system was fully populated ( ie, a handset is already # 5 )
you will have to clear all the handsets from the base and
re-register them in sequence ( it is the only way to 'rescue' the
places occupied by the lost handsets ).
To clear the base of all registrations:
1. Press and hold the the "Handset Locator" button until the
"in use" light lights and then starts to blink ( ~ 10 seconds ),
release the button -- then press it again briefly while the "in use"
light is still blinking.
2. The base will beep and all handsets will display
3. Follow the instructions above for each handset in turn: press
"Handset Locator" ~ 4sec ( in-use light on ), set handset into
the base cradle, etc.
The manual is available from: www.manualslib.com
but does not describe these procedures.
Good luck !