Specifications

Loop Current Reference Manual (MGCP/NCS Version)
Mediatrix 4100
131
Loop Current
When one of its analog lines goes off-hook, the Mediatrix 4100 controls the line in a fixed loop current mode.
The value of the loop current can be modified through the MIB.
Note that the actual measured current may be different than the value you set, because it varies depending
on the DC impedance. This is illustrated in Figure 28
for a loop current of 32 mA.
Figure 28: Loop Current vs Impedance – 32 mA
 To set the loop current:
1. In the fxsMIB, set the fxsLoopCurrent variable to the value you want to use.
The loop current is in mA. The range of available values is from 20 mA to 32 mA.
This value applies to all the endpoints of the Mediatrix 4100.
2. If you want to set a different loop current value for one or more endpoints, set the following variables:
• fxsEpSpecificLoopCurrentOverrideEnable variable for the specific endpoint you want
to configure to enable.
• fxsEpSpecificLoopCurrentOverride variable for the specific endpoint you want to
configure with the proper loop current value.
3. Restart the Mediatrix 4100 so that the changes may take effect.
When a remote end-user goes on-hook, the Mediatrix 4100 signals the far end disconnect by performing a
current loop drop (< 1 mA) on the analog line. This current loop drop, also referred to as “Power Denial” mode,
is typically used for disconnect supervision on analog lines. The Mediatrix 4100 maintains a current drop for
one second (this value cannot be configured), then a busy tone is generated to indicate the user to hang up.