AT&T SYSTEM 25 Manual page 63

Turning On the HFAI Feature
Press
The light next to this button turns on.
Answering an Inside Call
1 Listen for the beep that announces a call.
The lights next to [MICROPHONE] and [SPEAKERPHONE]
on the HFU turn on.
2 Begin speaking.
NOTE:
you, press
The light next to this button will turn off.
When you want to resume your conversation with the caller,
press
The light next to this button will turn on.
Ending an Inside Call
If the caller hangs up, you will be automatically disconnected.
Otherwise, press
The lights next to [SPEAKERPHONE] and [MICROPHONE] turn off.
Turning Off the HFAI Feature
Press
The light next to this button turns off.
2-50 Voice Terminal Features
[AUTO ANS].
If you want to temporarily keep the caller from hearing
on the HFU.
[MICROPHONE]
again on the HFU.
[MICROPHONE]
[SPEAKERPHONE
.
[AUTO ANS]
] on the HFU.