Panasonic KX-TGM420 Operating Instructions Manual page 172

Problem
I cannot hear a
dial tone.
172 | P a g e
Cause/solution
27).
• Unplug the base unit's AC
adaptor to reset the unit.
Reconnect the adaptor and try
again.
• The handset has not been
registered to the base unit.
Register the handset (page 127).
• The base unit's AC adaptor or
telephone line cord is not
connected. Check the
connections.
• Disconnect the base unit from
the telephone line and connect
the line to a known working
telephone. If the working
telephone operates properly,
contact our service personnel to
have the unit repaired. If the
working telephone does not
operate properly, contact your
phone service provider.