2 – Functional Description & Setup
Intraplex VF-40 Voice Module
Version 1.11
GatesAir
2-3
Intraplex Products
The PCM CODEC converts the eight-bit digital signal back to an analog audio signal and passes it to an
electronic level control, which allows the output level to be adjusted up or down in <0.1 dB
increments.
The audio output passes to an amplifier stage and finally to the output connectors on the module
adapter. Switches on the module allow the nominal output level to be set to +7 dBm.
2.3 Alerts/Alarms
The VF-40 module reports no module-level ALERT or ALARM signals to the shelf common module.
2.4 Loopbacks
The VF-40 module provides two loopback types:
●
Local loopback of all four channels, used for testing the operation of the module during initial
installation
●
Remote loopback of each channel individually, used when troubleshooting channel problems
Figure 2-3 shows these loopback locations. Section 4 – “Testing and Troubleshooting” provides
procedures for using these loopbacks.
2.5 Drop and Insert Operation
A drop and insert multiplexer operates at a central point on a three- (or more) point system. In Figure
2-2, Site 2 has a drop and insert multiplexer whose DI/A port is connected to the transmission line to
Site 1 and whose DI/B port is connected to the transmission line to Site 3. Individual payload channels
may connect Sites 1 and 2, 1 and 3, or 2 and 3.
Note:
In the drop and insert multiplexer at Site 2, a VF-40 module can be set to transmit and
receive through the DI-A port (toward Site 1) or the DI-B port (toward Site 3) but not both.
When a VF-40 module is installed in a terminal multiplexer (Site 1 or Site 3), its TERM switch must be
set DOWN. However, when it is installed in a drop and insert multiplexer (Site 2), the TERM switch
setting must be DOWN to transmit or receive through the DI/A port (toward Site 1) and UP to transmit
or receive through the DI/B port (toward Site 3).
Site 2
Drop and Insert Multiplexer
Through Channels
Site 3
Terminal
Multiplexer
To/From
Site 1
(TERM
Switch
DOWN)
To/From
Site 3
(TERM
Switch
UP)
Drop and
Insert
Channels
D/I
A
D/I
B
Site 1
Terminal
Multiplexer
To/From
Site 2
(TERM
Switch
DOWN)
T1 or
Aggregate
Circuit
To/From
Site 3
(TERM
Switch
DOWN)
To/From
Site 1
(TERM
Switch
DOWN)
To/From
Site 2
(TERM
Switch
DOWN)
V
F
4
0
V
F
4
0
V
F
4
0
V
F
4
0
V
F
4
0
V
F
4
0
T1 or
Aggregate
Circuit
Figure 2-2. Example of Three-Site System Using Drop and Insert
