The input/output levels of a voice channel are set at the factory for a default value of 0/0 dB. At some installations, the input/output levels need to be adjusted to compensate for external network losses and variations, to optimize the voice compression operation, and to provide a consistent communication level throughout the network.
However, no adjustment within the voice circuits can correct for voice distortions prior to the arrival at the input of the voice port, or for unusual impedances inherent in the external network.
The objective of these procedures is to obtain an input level of -4 dBm, and achieve an overall circuit loss ranging from 8 to 16 dB without introducing an input gain setting of more than 6 dB to achieve it. An excessive input gain setting may cause echoes or other voice impairments such as ringing or repeated DTMF signaling digits. Set any voice channels not under test to forced On busy condition to insure that the test calls operate only through the channels under test.
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Note: These procedures are intended for equipment operated outside of the U.S.A. and Canada, and must meet the standards of the country wherein the equipment is used. Perform these procedures only if your country does not require specific input and output level settings. |
The following topics are discussed in this section:
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