Matrix Visionpro System Manual page 58

This way a station user who does not have permission for long distance calling, can dial out a long
distance number. This situation can be prevented by setting the Speech Delay Timer to an appropriate
value. It can be configured for individual trunks.
• CLI type: Define the Calling Line Identification (CLI) format for the CO line by selecting the format
supported by your service provider. Regarding this, you may consult the service provider of the selected
trunk line. VISIONPRO detects the CLI sent by the CO network and sends this information to the landing
station/operator with the ringing signal.
• Pause Timer: It is the time for which the system waits before dialing out a number after grabbing the trunk.
This timer inserts delay when digits of a number string are out dialed from the CO trunk.
Some times it is observed that after grabbing the trunk line, the user does not get PSTN Dial Tone
immediately. Instead he/she gets the Dial Tone from the PSTN after some time. This normally occurs in
older types of PSTNs. When user is dialing the number, he/she inadvertently waits for the Dial Tone and
then dials the number. But this is not so when the PBX dials the number. When Redial or Auto Redial or
Abbreviated Dialing feature is used, the PBX grabs the trunk line and dials out the number at its own. Now
if there is no pause time programmed, then for older PSTN systems it is possible that the PBX may dial out
the number before getting the Dial Tone from the PSTN. This may result in dialing of wrong numbers. To
avoid such instances, VISIONPRO offers this timer, which can be set for individual trunks. Pause Timer is
used during Redial, Auto Redial and Abbreviated (Memory) Dialing.
• Receive Gain and Transmit Gain: You can increase or decrease the level of Incoming Speech (Receive
Gain) and Outgoing Speech (Transmit Gain) on the trunk port by changing the Rx Gain and Tx Gain
respectively to the desired level. Different levels can be set for each trunk port type.
• AC Termination Impedance: The AC Termination Impedance (or simply, the AC Impedance) of the CO
port must match to the AC Termination Impedance supported by the PSTN network.
• CO Termination: This parameter allows you to increase the near-end echo cancellation on the CO trunk.
Near-end echo is primarily caused by the mismatch between AC Termination Impedance (presented by
the CO port of VISIONPRO to the line) and CO Termination (Impedance presented by the Central Office to
the line), and to some extent by the transmit and receive signal path.
By correcting the line impedance mismatch, you can increase the near-end echo cancellation. This is done
by configuring the AC Termination Impedance and the CO Termination, and then selecting a CO Line Type
(see the next parameter) that most closely resembles the line that connects the CO port of VISIONPRO to
the Central Office.
Configuring the correct CO Termination value depends on the region where VISIONPRO is deployed. For
example, if AC Termination Impedance in your location is 600and the CO Termination impedance is
900 in series with 2.16µF, then configure AC Impedance as 600and CO Termination as 900 + 2.16µF.
You are recommended to conduct the AC Impedance Test for the line connected to the CO port on which
you will apply this configuration. The AC Impedance Test will help you to determine the most appropriate
values for the AC impedance, CO Termination and the CO Line Type. For more information see the topic
"AC Impedance
• CO Line Type: This parameter allows you to configure the Line model for the CO Termination you have
selected. You need to configure a line type that most closely resembles the line connecting VISIONPRO to
the Central Office. To configure the CO Line Type, you may select a specific EIA line model from the eight
available options (EIA-0 to EIA-7) or a specific wire gauge and length (2000 ft. 22/24/26awg).
Matrix VISIONPRO System Manual
Test".
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