Media5 Mediatrix 4104, Reference Manual

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Chapter 14 - Line Configuration Line Reversal
226 Mediatrix 4104
Line Reversal
Two options are available to determine how the line polarity is used to signal the beginning and end of a call.
They are used because of an inability by some customer's CPE to react to busy tone. When one of the options
is activated, it replaces the default behaviour of the Mediatrix 4104, which is to briefly remove power from the
line to signal that the remote party has hung up.

To enable line reversal:
1. In the fxsMIB, set the fxsPolarityAndDenialBehavior variable with the proper parameter.
2. Set the fxsPowerDropOnDisconnectDuration variable with the power drop duration, in milliseconds,
that is made at the end of a call when the call is disconnected by the remote party.
This variable only has an effect when the variable fxsPolarityAndDenialBehavior is set to
noReversal .
Blanking of an Anonymous Caller ID
You can instruct the Mediatrix 4104 to blank out the name portion of the received caller ID whenever
“anonymous” (case insensitive) is used to identify the originator of the call before the caller ID data is sent to
the telephone. If the variable is not activated, the anonymous string is passed on to the telephone and
displayed to identify the calling party.

To enable anonymous caller ID blanking:
1. In the fxsMIB, set the fxsBlankAnonymousCallerId variable to enable .
Table 139: Line Reversal Parameters
Parameter Description
noReversal Polarity reversal is not used. This is the default value. A short power
drop is made at the end of a call when the call is disconnected by the
remote party. The drop duration can be configured in the variable
fxsPowerDropOnDisconnectDuration (Step 2).
reversalOnIdle Activates the Reversal on Idle feature. When a line is in the idle, line
lockout, or blocked state, the polarity of the line is reversed. When the line
is seized to originate a call, or the ring current is applied to terminate a
call, the line polarity is returned to normal. On release, the line polarity is
returned to the reversed condition.
reversalOnEstablish
ed Activates the Reversal on Established option. The polarity remains
normal (voltage on the phone line stays positive) when you pick up the
phone, dial, and when the device is ringing. As soon as the other party
picks up the phone, the unit reverses the line polarity. When the unit
receives a hang-up signal or the caller hangs up the phone, the voltage
returns to its positive state.