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OVERVIEW
The VLBRV (Very Low Bit Rate Voice) or VLBRV/FAX Channel Module is an analog voice
channel card for the MEGAMUX PLUS TDM. It provides voice encoding algorithms that max-
imize voice channel bandwidth utilization while offering low bit rate values of 9600, 4800 and
2400 bps. The VLBRV Channel Module is used in transmission applications to maximize avail-
able bandwidth. Applications include use in digital services such as ASDS (FT-1), ADN, satellite
and in feeder applications in which a customer needs to integrate both voice and data. Voice com-
munication is two-way simultaneous (full duplex). The VLBRV Module mounts into the MEGA-
MUX PLUS channel or expansion shelf.
This errata sheet covers all aspects of the VLBRV Channel Module configuration, diagnostics,
alarm and status scans as seen on the MEGAMUX PLUS supervisory controller screens.
DEFINING VLBRV CHANNEL PARAMETERS
Channel parameters are selected in a logical sequence. You must first specify the number of the
channel that you wish to configure. Once a channel number is selected, you enter the voice chan-
nel type. Once a channel type is selected, there are a range of parameters to be selected. You are
not allowed to select these parameters until a channel type is specified. Figure 1 shows how the
VLBRV channel parameters are configured.
CURRENT PARAMETERS FOR CHANNEL #01
CHN
CIRCUIT
#
TYPE
01
VLBRV
Channel Number
The channel number associates a set of channel parameters with a VLBRV Channel Module in
the MEGAMUX PLUS TDM shelf. The channel number is determined by the position of the VL-
BRV Channel Module in the shelf. Channel numbers range from 1 up to a maximum of 54 (you
must have one expansion shelf for a system with up to 38 channels, and two expansion shelves
for a 54-channel system).
(55$7$#6+((7
MEGAMUX PLUS TDM
OPERATOR'S INSTRUCTIONS
Publication No. 036R660-000, Issue 9
CIRCUIT
BAUD
NAME
RATE
MIKE1
9.6K
FIGURE 1. CHANNEL PARAMETERS
FOR
CONFIGURATION AM
T-R CLK
TID-IR OR
VF-DB-LEVEL
M/S
DATA STOP
___
___
0.0
I/F
TID
M
S
TYPE
MODE/DELAY
0.0
VC_1
___
036R660-E1
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