Specifications

6-4 FXS Ports
Model No.
Running Head
Tx TLP
The Transmit TLP setting controls the amount of gain or loss added to a voice signal from the
CPE before it is encoded to digital PCM. To increase the signal level, set the Tx TLP setting
to a negative value (i.e., the more negative the number, the more gain is added). To decrease
the signal level, set the Tx TLP setting to a positive value (i.e., the more positive the number,
the more the signal level is decreased). For example, an incoming signal at -5 dBm can be
increased to -2 dBm by setting the Tx TLP to -3 dB. The Tx TLP range is -3.0 dB to +9.0 dB.
CODING
The Coding setting sets the PCM companding method used for a port. Generally, the North
American T1 environment uses u-law coding. This parameter will impact all four FXS ports.
The default coding setting is determined by the type of associated WAN port.
LB
The Loopback field lets you loop the port back toward the network and far end. The dgtl
(digital) loopback sends the incoming digital DS0 signal back to the far end without decoding
it. The anlg (analog) loopback sends the decoded analog signal back to the far end after
decoding and then re-encoding it. Figure 6-2 shows the loopback options, which allow you to
test and troubleshoot the FXS port. To disable a loopback, set this field to off.
Figure 6-2. FXS port Loopbacks