Siemens TC35i - Manual (Page 22)

TC35i Terminal Hardware Interface Description
Confidential / Released
TC35i_T_HD_v01.05 Page 22/37 10.07.2003
3.6.2 Audio interface
The audio interface provides an analog input for a microphone and an analog output for an
earpiece.
· The microphone input and the earpiece output are balanced.
· For electret microphones a supply source is implemented.
· The microphone supply characteristics are optimized for the recommended Votronic
handset. For ordering Information see Chapter 7.
· This handset has been used as the reference handset for type approval. An extra
approval must be obtained for integrating other handsets or amplifiers.
The amplification of sending direction, receiving direction and sidetone depend on the
current audio mode.
EMC immunity complies with the vehicular environment requirements according to
EN 301 489-7.
Figure 6: Audio Western plug (4-pole female)
A
D
A
D
-¥...0dB
speechcoder
0dB; -6db, -
12dB; -18dB
+0..42dB in
6dB-steps
4k7
4k7
5.9V
6R8
6R8
+
(sideTone)
( ) AT parameter
(outCalibrate[n])
n = 0...4
(inCalibrate)
(inBbcGain)
(outBbcGain)
speechdecoder
Ri=2k
MICP
MICN
EPP
EPN
Figure 7: Audio block diagram
Pin assignment:
1 MICN (Microphone - )
2 EPN (Earpiece)
3 EPP (Earpiece)
4 MICP
1
2 3
4
(Microphone +)