How to Configure a Virtual Tie Line 89Conference Calls Involving Site Codes and Off-Site TelephonesIn Figure 11, you work in the Chicago office and want to establish aconference call with someone in Atlanta, someone in Dallas, andsomeone at an external telephone number, you:1 Dial the Atlanta site code (62) and then the extension.2 After the Atlanta user answers, press Conference and dial the Dallas sitecode (63) and then the extension.3 When the Dallas user answers, press Conference again to connect allthree users.4 Press Conference again and dial the external telephone number.If the site requires that you dial 9 to reach an outside telephone line, andif the call is a long-distance call, the user might dial a number in areacode 367 using the digit sequence 913675551212.5 When the person answers, press Conference again to connect all fourusers.How to Configure aVirtual Tie LineConfiguring a working VTL connection between two systems involves:■ License Installation■ Dial Plan Configuration■ Updating the Extension List■ Adding VTL Devices to the Pretranslators (Optional)■ Verification of the Virtual Tie LineYou can enable silence suppression and different levels of audiocompression for your VTL calls. For more information on how silencesuppression and compression affect bandwidth, see “Audio Settings” onpage 257. To change the system-wide settings for silence suppressionand compression on VTL calls, use the NBX NetSet utility to edit the audiosettings: System Configuration > System Settings > Audio Settings.License Installation ■ You must obtain and install a license to enable VTLs.■ Each VTL license applies only to the NBX system on which it isinstalled. To connect three sites by VTLs and to have each site supportup to 8 simultaneous active VTL connections, you must install aseparate license key for 8 VTLs on each of the three NBX systems.
