Telit EVK2 User Guide
1vv0300704 Rev.13- 2012/06/25
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved
page
33 of 149
9.
Audio outputs
The EVK2 output audio signals could be drive a device connected to
SO401
(
LOW AF POWER
mode
) or to
PL401
(
HIGH AF POWER mode
).
9.1.
Low AF Power Mode
Inserting the
2 contacts jumpers
as explained at paragraph 9A, a standard
off-the-shelf
Headset
should be connected to the
SO401
(
3 contacts, 2.5mm diameter jack connector
).
With such an insertion, the Telit Modules will power the Microphone through a Single
Ended input circuit and the Earpiece through a Single Ended/ AC coupled output circuit.
NOTE:
The acoustic performance of the
Headset
(
frequency response, loudness
) largely depends by its
housing, fitting and acoustic impedance.
The coil impedance of the Headset should be higher than 15 ohm @ 1KHz.
headset.skd
HEADSET
SPEAKER
RS232
STACKED
USB
RS232
CS1139B
1
40
39
1
AUDIO 2
AUDIO 1
29
PL102
30
Figure 14: Headset insertion
Common GND
Earpiece
2
1
MIC +
3
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