Panasonic KX-TG2750S Operating Instructions Manual page 58

If the Following Appear on Your Display...
Display message
Error!!
8 handsets have
already been
registered.
(cordless handset only)
58
• 8 cordless handsets have already been registered to
the base unit. To cancel another handset registration,
see page 54.
• This base unit has the memory of the cordless
handset currently registered to another base unit.
Erase the handset memory from the base unit.
For KX-TG2750S base unit:
(1) Press [FUNCTION/EDIT], (2) Press [MUTE],
(3) Enter "335#" and (4) Enter that handset number
(1 to 8).
Cause & Remedy