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To allow users on one NBX system to place VTL calls to another NBX system and then place long-distance (toll) calls from that location (a practice called ‘hop off’), you can configure a VTL password.

When an NBX system receives a VTL call from a user on another NBX system, it can allow that user to make long-distance calls if the incoming VTL call contains the password. Otherwise, such calls are not allowed. If you set up two classes of VTL calls (with and without passwords), you can permit or disallow hop off.

To enable an NBX system to handle incoming hop off calls, create or modify a VTL password, as described in the next topic, Configuring a VTL Password.

To enable an NBX system to send hop off VTL calls, configure the dial plan to include the VTL password, as described in Configuring VTL Passwords in the Dial Plan on page 105.

Configuring a VTL Password

For each NBX system that can receive VTL calls, you use the NBX NetSet utility to configure a local system VTL password.

To configure the password:

1 In the NBX NetSet - Main Menu window, click System Configuration. 2 Click the Security tab.

3 Click the Virtual Tie Lines Password button. The Change Virtual Tie Lines Password dialog box appears.

4 Type the administrator password in the Current Admin Password text box. 5 Type the new VTL password in the New Virtual Tie Line Password text

box.

Passwords are from 8 to 15 characters in length and must contain only letters and numbers. Upper and lower case letters are permitted.

Using a VTL Password 105

6 Retype the new VTL password in the Re-enter New Password text box. 7 Click OK.

Configuring VTL Passwords in the Dial Plan

For each remote NBX system that controls hop-off by means of a VTL password, you must configure that password into the VTL commands in the local dial plan.

If you use site codes to access other NBX systems through VTL

connections, you can configure one set of VTL connections that permit hop-off and are accessed by one set of site codes. You can configure another set of VTL connections that do not permit hop-off and are accessed using a different set of site codes.

If you use unique extension ranges at each site, and therefore do not dial a site code when placing VTL calls to users at those sites, you can still use codes to access VTL connections that permit hop-off at the far end.

Figure 18 shows how to configure VTL passwords in a dial plan, using site codes that permit hop-off and other site codes that do not.

Figure 18 Dial Plan Entries for VTL Passwords

The first TableEntry Create command creates entry 100 in Table 1. This assumes that the highest previous entry in Table 1 was 99 or lower. Entry 100 watches for the 2-digit sequence 62 followed by a 4-digit extension and specifies route 522 whenever a user dials such a 6-digit (Min = 6 and Max = 6) sequence. Entry 101 watches for the 2-digit sequence 63

Table Create 1 Internal 4 Digit Extensions

/ Id Entry Digits Min Max Class Prio Route / -- --- --- --- --- --- ---- --- TableEntry Create 1 100 62 6 6 WAN 0 522 TableEntry Create 1 101 63 6 6 WAN 0 523 TableEntry Create 1 102 72 6 32 WAN 0 524 TableEntry Create 1 103 73 6 32 WAN 0 525

/ Route Description / --- ---

DestinationRoute Create 522 Atlanta VTL Connection DestinationRoute Create 523 Dallas VTL Connection

DestinationRoute Create 524 Atlanta VTL Connection with password DestinationRoute Create 525 Dallas VTL Connection with password

/ Route Entry DestinationExtension / --- --- --- DestinationRouteEntry Create 522 1 *0006

DestinationRouteEntry Create 523 1 *0006 DestinationRouteEntry Create 524 1 *0006 DestinationRouteEntry Create 525 1 *0006

/ Route Entry OperId Operation Value / --- --- --- --- --- DestinationRouteOperation Create 522 1 1 stripLead 2

DestinationRouteOperation Create 522 1 2 prepend 192*168*25*100* DestinationRouteOperation Create 523 1 1 stripLead 2

DestinationRouteOperation Create 523 1 2 prepend 192*168*35*100* DestinationRouteOperation Create 524 1 1 stripLead 2

DestinationRouteOperation Create 524 1 2 prepend192*168*25*100*ATLPassW* DestinationRouteOperation Create 525 1 1 stripLead 2

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followed by a 4-digit extension and specifies route 523 whenever a user dials such a 6-digit sequence. The choice of route numbers is made by the person configuring the dial plans for the sites.

The next two TableEntry Create commands are set up in a similar manner to handle VTL connections with passwords. If a user dials 72 followed by a 4-digit extension, the VTL call uses route 524. If a user dials 73 followed by a 4-digit extension, the VTL call uses route 525. These two commands specify a minimum of 6 digits (for example, if the caller is calling an internal extension preceded by the site code) and a maximum of 32 digits (for example if the caller is calling a long-distance or international number preceded by the site code).

The first two DestinationRoute Create commands create routes 522 and 523. The Description field contains text that describes each route. The second two DestinationRoute Create commands create routes 524 and 525, the routes that are used with a VTL password.

The four DestinationRouteEntry Create commands specify the extension list for routes 522, 523, 524, and 525. Extension list *0006 is the default extension list for VTLs.

For the first two DestinationRoutes, two DestinationRouteOperation Create commands perform two functions:

■ The stripLead command removes the two digits (62 or 63) leaving the

4-digit extension the user dialed.

■ The prepend command adds the IP Address of the destination NBX

system to the extension that the user dialed. In Figure 18, the IP address for Atlanta is 192.168.25.100; for Dallas, 192.168.35.100. In the dial plan, you must use an asterisk (*) instead of a period (.) to separate the fields within the IP address, and to separate the IP address from the destination extension.

For the second two DestinationRoutes, two DestinationRouteOperation Create commands perform two similar functions.

■ The stripLead command removes the two digits (72 or 73) leaving the

4-digit extension the user dialed.

■ The prepend command adds the IP address and system password of

the destination NBX system to the extension dialed by a user. In

password is ATLPassW. For Dallas, the IP address is 192.168.35.100 and the password is DALPWord. In the dial plan, you use an asterisk (*) instead of a period (.) to separate fields within the IP address and to separate the IP address from the destination extension.

To place a hop-off call to 555-1212 in area code 903 through the Atlanta system, a user on a remote system would dial 72919035551212. The 72 code sets up a VTL connection to Atlanta that incudes the Atlanta system’s VTL password, and the remaining digits are used to dial the number (9 accesses an outside line to obtain dial tone from the local carrier, 1 accesses the long-distance carrier, and the remaining digits specify the long-distance number).

If the same user used site code 62 to place a call to the Atlanta office, only toll-free, emergency, and internal call would be allowed.

Toll Calls Without a VTL Password

If a local user has configured his telephone to forward calls to a

long-distance number, then an incoming VTL call to that telephone does not need to supply the local system’s VTL password in order for the call to be forwarded.

Music On Hold If two users are talking on a VTL connection, and the first user places the call on hold, the second user hears Music On Hold only if his local system is configured to play it.

Troubleshooting VTL Calls

Table 22 contains a list of error situations, the possible causes and the action to take in each case.

Table 22 VTL Errors and Corrections

Error Condition Possible Causes Actions

Long pause after dialing. Telephone display contains “VTL” during the pause. Busy signal is then heard.

Remote server does not respond

Test the connection to the remote system using the Query Remote function.

Using a VTL Password 109

After you finish dialing a VTL call, you get a busy signal and the message “All ports busy” appears in the telephone display panel.

1. No VTL license installed. 2. VTL device extensions not added to Extension List *0006.

3. All local VTL connections are currently in use.

4. All VTL connections at the remote site are currently in use.

1. Verify that the licenses appear when you access the tab.

2. Verify that the *0006 extension contains the VTL device extensions.

3. On the Virtual Tie Line tab, verify that there is at least one idle VTL connection.

4. Use the Query Remote function to verify that there is at least one idle VTL

connection. After you finish dialing a VTL call, you get a busy

signal and the message “Invalid Number” appears in the telephone display panel.

1. Local dial plan is not properly configured. 2. Dial plan on the remote (target) system in not properly configured.

3. You are trying to use hop-off without the necessary password.

1. Examine the local dial plan for errors.

2. Examine the dial plan on the remote system for errors. 3.Verify that the password for the remote system is used in both dial plans.

No audio 1. Telephones are not

configured to use either IP On-the-Fly or Standard IP. 2. VTL Audio compression is supported on only one of the two NBX systems.

3. 3C10165D E1 and 3C10116D T1 Digital Line Cards do not have static IP addresses.

1. Verify that the IP setting in the System Settings,

System-wide dialog box is “IP On-the-Fly” or “Standard IP.” Change the setting, if necessary.

2. Verify that audio compression is enabled on both systems.

3. If your NBX system is set up for IP-On-the-Fly, verify that 3C10165D E1 and 3C10116D T1 Digital Line Cards have a static P address. These cards cannot receive an IP On-the-Fly address. Caller ID information does not appear correctly in

the telephone display panel.

1. Invalid local pretranslator. 2. VTL extensions are not in the VTL pretranslator “Devices Using” table.

1. Examine the local dial plan for pretranslator errors. 2. Verify that VTL extensions appear in the left-hand table for the pretranslator.

Table 22 VTL Errors and Corrections (continued)

Dial Plan

Configuration File