Sony SPP-A985 - Manual (Page 52)

52 US Answering Machine Features
Note
The answering function is preset to on.
Tip
The answering machine will automatically answer a call after 10 rings, even if
the answering function is off and announces “Please enter your security code”
to prompt the caller to turn on the answering function.
When the memory is full
The total recording time of this answering machine is approximately
15 minutes (including the greeting, messages, and memo).
When the remaining recording time becomes less than 30 seconds, “F”
flashes on the display and the answering machine goes into the
memory full status.
In this status, the answering machine will not answer a call until after
10 rings even if the answering function is on.
To avoid this erase unnecessary messages (see page 54). You can also
erase the messages from an outside phone (see page 59).
Setting up the answering machine (continued)