Nokia 2600 服务手册

ISSUE 1 09/2004

COMPANY CONFIDENTIAL

19

Copyright © 2004 Nokia. All Rights Reserved.

RH-59/60

7-System Module

Nokia Customer Care

■ 

Nokia 2600 is designed to support fully differential external audio accessory connection. A 
headset and PnPHF can be directly connected to system connector. 

Headset accessory uses 4-wire fully differential audio connection. 

The earpiece selected is a 8-mm dynamic earpiece from PSS with a nominal impedance of 32 
W. The earpiece acoustics will be designed to be type approved by type 3.2, low leak artificial 
ear (Ear Simulator Type 4195, Low Leakage).

The earpiece will be mounted into the UI-shield assembly, the sealing of the back and front vol-
ume will be implemented in the UI-shield by die casting. This sealing part will also provide the 
sealing against the A-cover.

To achieve a small dynamic range of the earpiece frequency response, a helmholtz resonator 
is implemented in front of the speaker membrane, the resonance frequency of the helmholtz 
resonator is approximately 4 kHz.

To improve the leak tolerance of the earpiece design leak holes will be implemented. The holes 
will provide a leak from the A-cover to the internal phone volume.

Dust and water shield is used to reduce the total dynamics of the frequency response by atten-
uating the resonance, it will also protect the earpiece from pollution with dust and swarfs.

1k0 

Hookint  

Headint  

Headint  

EAD 

MICB2  

MIC2P  

MIC2N  

33N 

HFCM  

HF 

Bottom 
Connector  

UEM  

2.1V 

2.7V 

33N 

1k0 

/MBUS  

MicGnd  

1.8V 

0.3V 

0.8V 

 

Mic_bias  

0.8V 

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