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TruVision NVR 40 unit overview
Interface module
The interface modules provide additional low-cost, non-isolated serial
communication ports and I/Os.
Figure 4: Interface module
Serial port
The half/full duplex wiring selection is done by software, controlling both the H/F
input pin of the transceiver that internally connects Tx and Rx as well as selective
enabling for the receive and Transmit drivers. A switch enables the termination
resistor. Rx and Tx resistors are activated independently. Terminations are enabled by
default. Serial ports have been ESD protected. The differential drivers/receivers used
(MAX3089E), offers the following characteristics:
• Fail safe Receiver
• RS-422/RS-485 electrical compatibility
• Enhanced electrostatic discharge protection
• Selectable between half and full duplex operation
Transistor I/Os
The 4 general-purpose inputs are pulled up to high level and trigger when the circuit
is closed to the ground (active low). Inputs allow high level up to 48V. When an input is
high, its respective LED is OFF. The LED is ON when the input is grounded.
The 2 general outputs are open collectors (normally open). The maximum output
current is 500mA and outputs are able to switch signal of up to 48V. Led is OFF when
output is open. LED is ON when output is grounded (or closed).
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TruVision NVR 40 User Manual
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