ViaSat VMBR-1520, Инструкция по установке, эксплуатации и обслуживанию, Страница: 32 / 88

VMBR-1520 Mobile Broadband Router Installation, Operation, and Maintenance Guide
Preparation for Use and Installation
1075152 Rev. 001
2-14
2.3.3.1 Coaxial Connections
DC power to the BUC and LNB are provided by the VMBR-1520
through the Tx and Rx IFL coaxial cables. These cables need to be
properly sized for the current capacity and to minimize voltage drop
across the cables.
Both Tx RF (J2) and Rx RF (J3) ports have a characteristic impedance
of 50 Ω. The IFL cables should have a characteristic impedance of 50 Ω
to minimize reflection on the cables and ensure maximum power
transfer from the modem to the antenna.
2.3.3.2 ACU Connections
Communication between the VMBR-1520 and the ACU can be made via
the serial EIA-422 interface.
To use the serial EIA-422 interface, connect a 9-pin serial cable
between the ACU’s EIA-422 port and the modem’s ACU port (J4). Refer
to Table 2-3 for pin descriptions. All signal names are relative to the
modem.
Table 2-3. ACU Port (J4) Pin Descriptions
Pin Signal Description
1 SHLD+ Cable Shield
2 TXD+ Transmit Data +
3 RXD+ Receive Data +
4 GND Ground
5 GND Ground
6 N/C --
7 TXD- Transmit Data -
8 RXD- Receive Data -
9 N/C --
Warning Do not
disconnect the IFL cables to
the antenna when the unit is
powered on. A DC voltage is
present on the IFL cables.
The unit could suffer damage
if the IFL cable is
accidentally dropped onto a
metal object.