U9500 Maintenance Guide
9 Troubleshooting
Issue 1.2 (2012-6-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
38
Subsystem Module
Unit
Function
User ports
UART card
connector
The UART1 port in the AP is connected to modem,
UART2 connected to Bluetooth&GPS, UART3 connected
to commissioning equipment, UART4 connected to audio
noise reduction chip ES305.
USB
connector
Driver, protective
circuits, and
output interface
Indicates the USB peripheral circuit, protective circuit, and
interface connector in the AP, modem, and MHL
subsystems. The USB interface is a main data service
channel for an engineering prototype and is also used for
commissioning and test during the R&D process.
USIM
connector
Power supply,
protective circuit,
USIM socket
USIM card socket and related connection circuits.
Keypad and
backlight
Keypad drive
circuit, external
keypad, LED
backlight control
circuit
The volume keys are monitored using the interruption
monitoring method through the GPIO.
When users press the volume key, the two top view LED
backlights are on.
Color LCD
and backlight
LCD driver,
interface mode,
and backlight
control
Size: 4.5 inches
Category:TFT
Resolution: 1280 x 720 pixels (HD)
microSD card
Power supply,
protective circuit,
and connector
microSD card connector and related interface circuits.
Speaker
Drive mode,
connection mode,
and speaker
related
components
Plays polyphonic ringtones when a call is received. Its
power is up to 500 mW. Features good frequency response
to play 20 kHz audio and can also be used as a mono
speaker to play MP3.
Receiver
Drive mode,
connection mode,
and receiver
related
components
Power: < 30 mW
MIC
Interface circuit,
connection mode,
and microphone
related
components
Embedded two silicon microphones in favor of noise
reduction.
Headset
Earphone,
headset interface
circuit, and
microphone
interface circuit
The phone provides headset interface for call output or
MP3 output while the microphone is set on the earphone
line to transmit the sound to the phone.