Multitech MVP200 User Giude page 26

16. To change the voice coder, select the channel from the Select Channel list, then select the
new voice coder entry from the Voice Coder list.
If you changed the voice coder, ensure that the same voice coder is used on the voice/fax
channel you are calling. Otherwise, you will always get a busy signal.
17. If you selected the FXO interface and are using touchtone dialing, you can set up the DTMF
gain (or output level in decibels - dB) for the higher and lower frequency groups of the DTMF
tone pair. Make your selections from the lists in the DTMF Gain group.
Note: Only change the DTMF gain under the direction of Multi-Tech Technical Support.
18. The Fax group enables you to send and receive faxes on the selected voice/fax channel. You
can select the maximum baud rate for faxes from the list in the Fax group. If you do not plan
to send or receive faxes on a given voice/fax channel, you can disable faxes in the Fax group.
Note: After configuring a given channel, you can copy that channel's configuration to any other
channel by clicking Copy. Everything on the Voice/Fax tab will be copied to the other chan-
nel.
19. You can enable the voice/fax advanced features by selecting the Silence Compression,
Echo Cancellation, or Forward Error Compression check boxes in the Miscellaneous
group.
The Silence Compression check box defines whether silence compression is enabled for the
selected voice channel. If enabled, the MultiVOIP will not transmit voice packets when silence
is detected, thereby reducing the amount of network bandwidth being used by the voice
channel.
The Echo Cancellation check box defines whether echo cancellation is enabled for the
selected voice channel. If enabled, the MultiVOIP will remove echo-delay, which improves
sound quality.
The Forward Error Correction (FEC) check box enables recovery of some corrupted or lost
voice packets. FEC adds 50 % overhead to the total network bandwidth.
Chapter 3 - Software Loading and Configuration
26