Geemarc Serenities User Manual page 37

Menu Functions
After turn on " Auto turn on " and set the Pin code, you can use
the function as follows.
After 10 times ringing is detected, the phone will be auto offhook
the line (In this state, the user can hear the caller but cannot
answer the call), and then generates two "bip-bip" tones to remind
the caller to enter Pin code to enter full speaker state. The caller
enters the Pin code, and then starts the conversation. Every 2
minutes later, the caller will hear a prompt tone. Then the caller
need to press any button to continue the conversation. Otherwise,
the line will be disconnected automatically.
NOTE: When the phone is auto off-hook the line, the user can
press the key to enter full speaker state. In this way,
there is no need for caller to enter Pin code.
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