The connector comprises the following pins:

Detection:

The detection of accessory is done by the charge pin and the detect pin.
Any accessory with an active charge will wake up the phone.
The insertion and removal of the charger (Cigar Lighter Charger, Desktop-Charger, AC-Charger) is detected via
polling. To reduce the power consumption the polling can take up to 5 sec.
The insertion and removal of other accessory is detected via an Interrupt. This detection is only possible when the
phone is powered up.

ID:

The ID pin indicates what kind of accessory is connected.

ACC power:

ACC-power has different functionality with different accessories. ACC-power supplies power to the headset
(min.2.7V and min. 10 mA) or will be used as a signaling pin for the Hands Free Kit.
In the car-kit environment the ext. Vbat indicates that a phone call is accepted/in progress. This information is used
by the car-kit to power up the audio section of the car-kit, mute the car stereo and keep the car-kit powered up
even when the ignition is switched off.
Due to the fact that the ID of the accessory is detected first, the ACC power is not current limited (protected).

RX and TX:

This is the communication interface to the PCMCIA card “QN-2PCM” or the PC-link cable ”QN-2EC”.
Audio In and Audio Out
These pins build the audio interface to the Head-Set and the Hands Free Kit.

Audio IN:

To limit the noise which is coupled on the Mic-line, the Mic amplifier in the Hands Free Kit “QN-CD5HFK” and
Head-set “QN-2HS” have an output 280mVrms into 10kW.

Audio OUT:

The single ended output delivers 265mV into a 32W load.