Ericsson DT288 User Manual page 18

If the battery is completely flat it can take a few minutes before the lower
green light on the charger comes on.
Changing the battery
Rechargeable batteries have a limited lifespan.
If the stand-by time for the cordless phone becomes too low, you should
replace the battery. Please contact your system manager or supplier for more
information.
Warning
Only use batteries as specified in "Technical specifications" on page 127.
The battery does not contain cadmium and is therefore more environmentally-
friendly than other rechargeable batteries. However, all batteries should be
treated as chemical waste.
Getting started 18