Page 58 of 910 Description
553-3001-365 Standard 4.00 August 2005
If the primary Signaling Server fails, the secondary Signaling Server takes
over (if it exists) and the IP Phones that were registered with the failed
Signaling Server reregister with the LTPS on the secondary Signaling Server.
If there is no secondary Signaling Server or the secondary Signaling Server
fails, the IP Phones register with the LTPS on the Voice Gateway Media
Cards.
For more information on Signaling Server failure and redundancy, see
Communication Server 1000S: Planning and Engineering (553-3031-120),
Communication Server 1000E: Planning and Engineering (553-3041-120), and
Signaling Server: Installation and Configuration (553-3001-212).

Virtual Terminal Manager

The Virtual Terminal Manager (VTM) performs the following functions:
• arbitrates application access to the IP Phones
• manages all the IP Phones between the applications and the UNIStim
messaging to the IP Phone
• maintains context-sensitive states of the IP Phone (for example, display
or lamp state)
• isolates IP Phone-specific information from the applications (for
example, the number of display lines, number of characters for each
display line, tone frequency, and cadence parameters)

Interactions with IP Phones

The following information describes the process by which an IP Phone
registers and unregisters with a Meridian 1 or CS 1000 system.
IMPORTANT!
Each Signaling Server supports the registration of up to 5000 IP
Phones.