NSW-6
System Module SE2
PAMS Technical Documentation
Page 33
Issue 1 12/99
Nokia Mobile Phones Ltd.
External Audio Connections
The external audio connections are presented in the figure on the
previous page. A headset can be connected directly to the headset
connector. The headset microphone bias is supplied from COBBA
AUXOUT output and fed to microphone through XMIC line.
Audio Accessory Detection
When the MCU–SW receives a headset–interrupt, generated by the
switch in the headset–connector, it will start the accessory–detection
sequence.
At first it will measure the voltage at XMICP–pin (divided in half by 2
resistors) via EAD AD–converter in CCONT. If it detects a voltage it will
start the sequence for the active accessory detection. The only specified
active accessory for NSW–6 is the PPH–3 handsfree kit.
If there is no active voltage detected at XMICP, AUXOUT–pin of
COBBA_D is switched to 1.5V and the voltage at XMICP is measured
again. The voltage at XMICP depends on the impedance which is
connected between XMICP and XMICN ath the accessory end.
Connector
Line Symbol
Minimum
Typical / Nominal
Unit / Notes
Connection
State
HOOKDET
(MAD1 pin C10)
HEADSETINT
(MAD1 pin B11)
Voltage at
XMICP
EAD–value
Notes
No accessory
connected
’1’
’0’
0V
0
Headset HDC–5
with button not
pressed
’1’
’1’
1.1V
390
When AUXOUT at 1.5V
Headset HDC–5
with button
pressed
’0’
’1’
0.75V
255
When AUXOUT at 1.5V
PPH–3 (con-
nected correctly)
’0’
’1’
2.6V
900
when muted
PPH–3 with ex-
ternal micro-
phone (con-
nected correctly)
’0’
’1’
2.2V
750
when muted
Audio box JBA-6
’1’
’1’
~0.9V
330 – 350
when AUXOUT at 1.5V
Internal Audio Connections (speech processing)
The speech coding functions are performed by the DSP in the MAD1 and
the coded speech blocks are transferred to the COBBA_D for digital to
analog conversion, down link direction. In the up link direction the PCM
coded speech blocks are read from the COBBA_D by the DSP.