523CLASS: Visual Message WaitingIndicatorContents This section contains information on the following topics:"Feature description" (page 523)"Operating parameters" (page 527)"Feature interactions" (page 528)"Feature packaging" (page 529)"Feature implementation" (page 529)"Feature operation" (page 531)Feature descriptionThe Custom Local Area Signaling Service (CLASS) Visual Message WaitingIndicator (VMWI) feature allows a CLASS set to receive a visual indicationthat messages are waiting. The visual indicator may be in the form of alighting or flashing Light Emitting Diode (LED), or a special message on aliquid crystal display, or both. The type of visual indicator depends on thefirmware of the CLASS set being used.For a non-Class set, lighting the Message Waiting Lamp through a highvoltage message (Voltage Message Waiting) is still supported and operatesin the same way as it did before.The visual indication message (an "ON/OFF" CLASS VMWI specificmessage) is delivered from the system to the CLASS sets using FrequencyShift Keying (FSK) signaling based on Bellcore specifications, using aCLASS modem (CMOD) unit. The CMOD units are configured using LD 13.Once configured, the CMOD units are shared throughout a multi-customersystem. When an FSK message is presented to a CLASS set, an availableCMOD unit is automatically allocated.Nortel Communication Server 1000Features and Services Fundamentals — Book 2 of 6 (C)NN43001-106 02.04 StandardRelease 5.5 9 May 2008Copyright © 1994–2008, Nortel Networks.
