Cisco Voice Log Translator 2.7(8) User Guide
Restrictions for Cisco VLT
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Restrictions for Cisco VLT

Restrictions for Cisco VLT

The following sections provide information on the restrictions for Cisco VLT version 2.7(8).


Cisco VLT supports only English operating systems and English locale.

File Types

Cisco VLT supports only Cisco Unified Communications Manager and Java Telephony Application Programming Interface (JTAPI) client message files.

Cisco VLT supports Cisco Unified Communications Manager SDI files but not Signal Distribution Layer (SDL) files:

  • This is true for versions prior to Cisco Unified Communications Manager 9.0.
  • For versions starting with Cisco Unified Communications Manager 9.0, SDI traces are interleaved in SDL trace files and Cisco VLT supports parsing of these interleaved SDL trace files.

System Resources

Cisco VLT can use significant system CPU and memory resources, and can potentially impact performance on a shared system. See the note in the System Hardware and Operating System section about the importance of installing Cisco VLT on a machine other than your Cisco Unified Communications Manager server.

Cisco VLT supports a maximum memory usage of 1GB. However, system performance may degrade before reaching the maximum value.

System Instances

You can install only one Cisco VLT in each system.

A maximum of two running instances, one standalone and one plug-in, are allowed at the same time.

System Performance

Cisco VLT installed on a 2.4GHz Intel Pentium 4 CPU performs as follows:

  • Installation time—5 minutes (approximate)
  • Program startup—20 seconds (approximate)
  • Memory consumption—Up to 10MB per 2.5MB of trace log file size
  • File loading—10 seconds (approximate) per 2.5MB of trace log file size


    Cisco VLT may exhaust memory if more than 100 SDI files of at least 2.5MB each are opened.

Display Capabilities

Although Cisco VLT supports both H.225 and H.245 messages, you cannot identify them because the H.245 port information contained in an H.225 message is not available in the Cisco Unified Communications Manager log files.

User Interface

For Cisco VLT running as a plug-in in Cisco Unified Communications Manager RTMT, the following applies:

  • There is no Cisco VLT menu bar. Functions that are provided by the menu bar in a standalone Cisco VLT (not running in RTMT) are provided by the Cisco VLT toolbar, pop-up menu on the 'Messages' table, or keystroke. To avoid conflict with RTMT functions, some keystrokes, such as F3 and Ctrl-F4, are disabled or behave differently for standalone Cisco VLT.
  • There is no Cisco VLT 'About window' for version information and 'Help Topics' function for online documentation. The online documentation link is referenced in the RTMT documentation launching function and the VLT plug-in version information is shown in the RTMT 'About window'.
  • There are no accessibility options.
  • There are no shortcut keys.


Cisco VLT supports only little-endian, and is not aware of the endianness of trace files.


Endianness refers to the order in which a computer processor stores and transmits the individual bytes of a multiple-byte data item. For more information see the glossary.