Tlp Settings - GE JungleMUX 86445-31 Technical Practice And Installation Manual

It is important to ensure that voice signals are transmitted at the correct level
across a network, so end-to-end performance is maintained. When transmitting,
too low a level can result in speech merging into background noise, while too
high a level can cause distortion. Signals that are to be transmitted onto a
transmission channel are attenuated to reduce the occurrence of echoes that
typically occur at 2-to-4 wire hybrid interfaces.
In Figure 13, the connection from phone to PABX is implemented through the
JungleMUX FXS/FXO combination. Setting the Transmission Level Point (TLP)
sets the VF level to which the actual transmit in and receive out signals are
referenced. The level set for the TLP becomes the 0 dBm0 level for that point in
the circuit (see note 2) and it is the dBm0 value that is transmitted end-to-end
over the link. The dBm0 value of a VF signal at the Transmit Input of an end-to-
end circuit is emulated at the Receive Output at the far end of the circuit. When
setting the TLPs it is important not only to keep the interface (telephone set or
PABX) requirements in mind, but also the end-to-end circuit as the Transmit TLP
setting at one end of the circuit directly effects the absolute receive level at the
far end of the circuit.
receive signal output at the far end without any adjustment to the transmitted
signal or the Receive TLP. Consider the following example:
• In an end-to-end circuit, the Transmit TLP is set for -5dBm and the far-end
Receive TLP is set for +2dBm.
• A VF signal of -10dBm is transmitted, which is 5dB below the reference
Transmit TLP, or -5dBm0.
• The information that the signal is 5dB below reference (-5dBm0) is
transmitted over the fiber link to the far end.
• The receive output signal at the far end will be -3dBm, 5dB below the
reference Receive TLP of +2dBm, or -5dBm0.
• If the Transmit TLP is changed to -3dBm, the same transmitted signal of
-10dBm is now 7dB below the new reference Transmit TLP (-7dBm0), so the
far-end receive output level will change to -7dBm0, resulting in an output level
change to -5dBm, 7dB below the unchanged reference Receive TLP of
+2dBm.
Copyright  GE Multilin Inc. 2002
APPENDIX A

TLP SETTINGS

Changing the Transmit TLP will change the absolute
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Issue 4.0
October 2006
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