Multi-Tech Systems MVP120 - Manual (Page 50)

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Chapter 7 - Using the MultiVOIP Software
Multi-Tech Systems, Inc. MultiVOIP User Guide
The Fax group enables a fax machine to transmit and receive faxes through the MVP120. If a
fax machine is connected to the via PBX port or PTSN, the Max Baud Rate should be set to
match the baud rate of the fax machine (refer to user documentation). The Fax Volume setting
controls the output level of the fax tones, and this setting should be changed only under the
direction of Multi-Tech’s Technical Support personnel. The Jitter Value setting defines the inter-
arrival packet deviation (in milliseconds) for the fax transmission. A higher value will increase
the amount of delay (allowing for a higher percentage of packets to be reassembled) and a
lower value would decrease the amount of delay (a lower percentage of packets would be
reassembled).
The Advanced Features group allows you to enable Silence Compression so that a MVP120
will not transmit voice packets when silence is detected, thereby reducing the amount of
network bandwidth that is being used by the voice channel; Echo Cancellation for the voice
channel will remove echo and improve the quality of sound; and, Forward Error Correction
allowing some of the voice packets that were corrupted (or lost) to be recovered. FEC adds an
additional 50% overhead to the total network bandwidth consumed by the voice channel.
Billing/Misc Tab
This tab controls the parameters for auto call, automatic disconnection, billing options, and
dynamic jitter buffer.
The Auto Call option allows the local MVP120 to call a remote MVP120 without the user
having to dial a Phone Directory Database number. As soon as you access the local MVP120
voice/fax channel, the MVP120 immediately connects to the remote MVP120 that you identified
in the Remote MVP120 Phone Number field of this option.
The Automatic Disconnection group provides three options which can be used singly or in
any combination. The Jitter Value defines the average inter-arrival packet deviation (in
milliseconds) before the call is automatically disconnected.The default is 20 milliseconds. A
higher value means voice transmission will be more accepting of jitter. A lower value is less
tolerant of jitter.
Consecutive Packets Lost defines the number of consecutive packets that are lost after
which the call is automatically disconnected. The default is 30 packets.
Call Duration defines the maximum length of time (in seconds) that a call remains connected
before the call is automatically disconnected. The default is 180 seconds. A call limit of three
minutes may be too short for most configurations. Therefore, you may want to increase this
default value.