DSB75 Development Support Board Rev. B1 Hardware Description
Confidential / Released
DSB75_hd_v12
Page 38 of 96
2008-08-26
3.6.2
Audio Interface 2 (Headset or Speakerphone Operation)
The unbalanced audio interface 2 is designed for use with headsets or speakerphones. The
interface is available on the 12-pin Lumberg connectors X700 and X701. The pin assignment
of the Lumberg jacks is shown in Table 15. The power for the microphone (VMIC) is supplied
by the GSM module. EPREF may be used for single ended loudspeaker configurations
saving an additional coupling capacitor.
Table 15: Pin assignment of audio interface 2 (X700, X701)
Signal name
X700 pin
X701 pin
I/O
Description
GND 1
2
-
Ground
Not relevant for audio.
R
2
-
4.7k resistor to pin 3, necessary
for old charger types.
Not relevant for audio
V
Charge
3
1
I
Supply voltage provided by the
plug-in charger.
Not relevant for audio
n.c.
4, 6, 7, 8
3, 4, 6, 7
-
Not connected.
Not relevant for audio
EPREF
-
9
-
100µF capacitor to AGND.
AC coupled loudspeaker ground
GND
5
5
-
5kOhm to GND.
AGND
9
11
-
Microphone and stereo
loudspeaker ground
MICP
10
12
I
Microphone not inverted.
EPP
11
10
O
Loudspeaker not inverted.
EPN 12
8
O
Loudspeaker
inverted.
3.6.2.1 Recommended
Headset
A standard headset interface for mobile applications is the Siemens Headset PTT HHS-510.
Please note that the headset interface has no detections for a device plug or Push-To-Talk
key (PTT).
