American Fibertek Net I/O N-664 - Manual (Page 18)

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Overview
The N-664 permits devices which use serial or contact closure signals to communicate
with each other to be connected over an Ethernet network. The N-664 acts as a virtual
cable connection, permitting signals to be sent between units as if there was a direct
connection between them. This allows the distance between customer equipment to be
greatly increased, and reduces the number of cables needed to connect multiple pieces
of customer equipment.
The N-664 makes serial ports and contact inputs and outputs accessible on a network.
Other devices on the network (including other VNES devices such as the N-664 or
Commander) can connect to these ports, or accept connections from them, allowing
serial data or contact closure events to be transmitted between devices. The N-664
comes with a configuration web interface which can be used to link serial and contact
ports on multiple N-664 devices together to provide a transparent connection between
customer equipment over the network.
In addition to providing transparent serial or contact connection between customer
equipment, the N-664 is also intended to work as part of a system with V’NES Pilot
software. This permits features such as logging of contact events or serial data.
Configuration of serial links and contacts differ in that serial connections are intended to
be point-to-point communication between two devices, while contacts can be set to
trigger various actions locally or remotely as desired. Each serial port or contact input or
output can be configured independently.
Each serial port can be set to act as either a Server or a Client port.
Serial Server Mode
In Server mode, the N-664 will make available a network port with a unique IP and Port
number. It will then wait passively for an incoming TCP/IP connection to that port.
When a TCP/IP connection is established, data sent to the N-664 through the TCP/IP
connection will be transmitted out on the hardware serial port, and data received on the
hardware serial port will be returned to the TCP/IP connection. This incoming TCP/IP
connection could be a made by another N-664 device in Client mode, another V’NES
product, or by a third-party device.
Data flow between the hardware port and the TCP/IP connection is bidirectional. The
rate at which data on the RS232 port is transmitted and received can be set through the
configuration web page. If the port is configured as an RS232 or 4 wire RS485 data flow
may be synchronous. A port configured as 2 wire RS485 must operate asynchronously,
where data reception will be inhibited while data is being transmitted out by the port.
Once a connection has been made to a port on the N-664, no other connection to that
port will be accepted until the connection is broken. Once the connection is broken the
N-664 will reset and re-open the port, and will wait for the connection to be re-
established.