Nokia N75 - Manual (Page 9)

Connect the audio adapter and headset
Connect the audio adapter AD-41 to the
Pop-Port
TM connector of your device, and
connect the headset HS-28 to the adapter.
1 Open the connector cover on the device.
2 Ensure the connector is ‘upside down’
before connecting to your device. Connect
the audio adapter connector. Do not use
excessive force.
3 Connect the headset to the audio adaptor.
Warning: When you use the headset,
your ability to hear outside sounds may
be affected. Do not use the headset
where it can endanger your safety.