Siemens VIU-20 Installation And Instruction page 20

TERM
VTP Virtual Local Area Network (VLAN) Trunk Protocol. A Cisco proprietary Layer 2
messaging protocol that manages the addition, deletion, and renaming of VLANs on a
network-wide basis. VTP reduces administration in a switched network. When you
configure a new VLAN on one VTP server, the VLAN is distributed through all
switches in the domain. This reduces the need to configure the same VLAN
everywhere.
WCM Wayside Communications Module. A radio, such as the MDS or Siemens ESSR
radios, located at a wayside and used to transmit vital status messages generated by
the VIU-20e to passing trains.
WIU Wayside Interface Unit. Term used to refer to the VIU in CBTC applications.
WSM Wayside Status Messages. Messages in EMP format reflecting the status of vital
functions at a wayside location. These vital functions include signal aspects and
switch positions. These messages are generated by the VIU and are sent to the WCM
for transmission.
SIG-00-07-11
Version No.: B.2
DESCRIPTION
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SEPTEMBER 2012 (REVISED OCTOBER 2019)