User's Guide

Internal back-up battery
The MDT-500-2mobile radio has a small rechargeable internal back-up battery.
This battery powers the internal Real Time Clock in the event that the main
power to the product is removed.
The battery may have discharged during the manufacturing process or if the
product has been in storage for some time. When the product is connected to
its main supply, the back-up battery will charge regardless of whether the
product is powered on or not. The charge period for a full charge may be up
to 48 hours.
User Guide
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