Specifications

Keypad Quality Control for Mobile Phones

Electronics Assembly

China

Introduction

One of the basic tests in the Quality Control of mobile phones is checking the output signals

after pressing keys on the keypad. This can be done manually by an operator (pressing the

keys one by one and verifying the signal output with a multimeter), but a far more efficient

and quality-assuring process can be created with a few Advantech I/O cards and a fixture. A

leading ODM mobile phone manufacturer in China created a solution with the PCI-1758UDIO

to drive mechanical silicon fingers, and a PCI-1711L to capture the output signals from the

phone. This simplified the operator’s tasks, reduced errors, and increased the overall speed

and efficiency of the testing process.

Project Requirements

In mobile phone production lines there are usually

many different models being quality tested

simultaneously, making it very problematic to depend

on a fully automated system. Human operators are

required in order to manually place each phone

into a corresponding test station, and make quick

judgments when discarding malfunctioning units. In

this type of production line, it is better to increase

the efficiency of human operators rather than work

towards creating an automated system.

Solution Description

The process starts with the operator placing the

phone in the test station’s fixture and pressing a

button. This sends a signal to a digital input channel

on PCI-1758UDIO, which initiates the test program

on IPC-6806. The test starts with PCI-1758UDIO

sending a digital output signal to a relay on the fixture,

which starts the mechanical process of pressing a

silicon finger towards the first key on the phone’s

keypad. At touchdown, several functions will activate

(depending on phone model).

If a numeric key is activated, a digital output code

for the Touchtone signal is output to PCI-1711L, and

compared to the correct codes by software.

Pressing a numeric key should also make the speaker

of the phone output an analog output signal at the

correct frequency. This is tested by an analog input

of PCI-1711L. For color LCD displays, the difference