Running the Line Impedance Test
Line impedance testing for FXO interfaces is done using the AnalogLineTest command through the device's Command Shell. The command runs the line test on a specified channel and for every specified impedance level (configured by a range), and then saves the results.
Before performing the line impedance test, you must upload a Voice Prompt file to the device.
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To run the line impedance test: |
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Access the device's Command Shell, which is done by appending "FAE" to the device's IP address in your Web browser's URL (e.g., http://10.13.4.13/FAE), and then clicking the Cmd Shell option located in the left pane. |
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On the command-line prompt, enter the AnalogLineTest command in the following format: |
AnalogLineTest <FXO Channel> <Impedance Low Limit> <Impedance High Limit> <Display Syslog>
Where:
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<FXO Channel>: FXO channel that you want to test and configure. |
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<Impedance Low limit>: Low level impedance value (0-15) that you want to test |
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<Impedance High limit>: High level impedance value (0-15) that you want to test |
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<Display Syslog>: Defines (0/1) if information is sent to syslog during the test |
The following example runs the test on FXO channel 4 with impedance levels 0 to 5 and sends the output to syslog (1):
>/VoiceEngn/AnalogLineTest>AnalogLineTest 4 0 5 1
Starting......
Check syslog for more information.
This command starts a test on channel 4.
Impedances 0-5 will be tested.
Messages are displayed in syslog during the test.
The following describes the sequence of events when you run the impedance matching test:
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The test is run using the AnalogLineTest command. |
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The tested channel is opened with default parameters and set to off-hook state. |
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The channel is configured with the low level impedance value. |
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A call involving the channel is started. |
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A PCM Voice Prompt file is played in the TDM direction. |
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The returned echo is recorded in a second PCM file. |
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Both of these files are scanned simultaneously and an ERL value is obtained. |
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The above steps are repeated for each of the specified impedance levels. |
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When the test completes, the channel is on-hooked and closed. |
The figure below shows the correlation between the impedance values in binary (0-15) and the actual impedance values (Ohms).
