Panasonic KX-FT25LA Service Manual ▷ View online
2.3.4.4.
Analog Board Section
The analog parts check is actually different than the digital parts check. The signal route is determined by the purpose of the check.
For example, the handset TX route begins from the handset microphone and is output in the telephone line. In this route, it is mainly
an analog signal. Tracing the signal can be done easily using an oscilloscope. Each route is shown on the 2.3.4.4.1. Check Seet
here. If there is a problem with the unit (for example, you cannot communicate with the H/S, etc.), trace the signal in the area and
determine the cause.
For example, the handset TX route begins from the handset microphone and is output in the telephone line. In this route, it is mainly
an analog signal. Tracing the signal can be done easily using an oscilloscope. Each route is shown on the 2.3.4.4.1. Check Seet
here. If there is a problem with the unit (for example, you cannot communicate with the H/S, etc.), trace the signal in the area and
determine the cause.
2.3.4.4.1. Check Sheet
Note:
{ }: Inside the digital board
[ ]: Inside the operation board
[ ]: Inside the operation board
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KX-FT25LA
Note:
{ }: Inside the digital board
[ ]: Inside the operation board
[ ]: Inside the operation board
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KX-FT25LA
2.3.4.4.2. Defective ITS (Integrated Telephone System) Section
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2.3.4.4.3. Digital Speakerphone
The digital speakerphone has different features from the analog speakerphone.
The analog speakerphone switches between Tx or Rx. Either Tx or Rx is able to pass through a telephone line or speaker,
depending on the Tx and Rx signal (voice) level. The higher-level signal (either TX or RX) can pass through the route.
depending on the Tx and Rx signal (voice) level. The higher-level signal (either TX or RX) can pass through the route.
Therefore, you never hear the other party´s voice while you are talking. However, the digital speakerphone allows you to hear the
other party´s voice while you are talking. So both Tx and Rx are active at the same time. There is also a defference in the
troubleshooting procedures between the two types.
other party´s voice while you are talking. So both Tx and Rx are active at the same time. There is also a defference in the
troubleshooting procedures between the two types.
At the start of communication, during the initial 2~3 correspondences, the digital speakerphone performs half-duplex operation,
alternating between transmission (Tx) and reception (Rx). Then duplex communication becomes available.
alternating between transmission (Tx) and reception (Rx). Then duplex communication becomes available.
Learning occurs during the initial 2~3 correspondences in order to set the appropriate parameters for duplex communication.
You cannot check the digital speaker phone by the signal route test mentioned in the Analog Board Section because the level is
always changing as stated above.
always changing as stated above.
Therefore, there is a service function for this troubleshooting. In this service mode, you can set the mute to either Tx or Rx. Then
you can check the signal route of the speaker phone Tx or the speaker phone Rx without any disturbances.
you can check the signal route of the speaker phone Tx or the speaker phone Rx without any disturbances.
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