Crestron electronic Ethernet - Manual (Page 15)

Crestron eServer™ Ethernet OEM Module
5. Custom Application Control of a Device Through the
eServer Utilizing Standard TCP/IP Sockets
This configuration is only for advanced designers. To implement a custom
application using this configuration, a designer must understand the low-level details
of how to program standard TCP/IP sockets. This communication path passes all
data through to the serial port (bypassing the SIMPL+ module). This feature provides
a "console" interface to the device through the Internet. Since this interface is a
standard socket, Telnet can be used as a console for the OEM designer's device. One
socket connection is allowed at a time.
Custom Application Control of a Device Utilizing Standard TCP/IP Sockets
Ethernet
eServer
Pass
Through
RS-232
Custom Application or Telnet
Serial
Data
Standard
TCP/IP Socket
DEVICE
The eServer provides a TCP/IP socket so that custom applications can connect to the
device through the network. The socket provides a “pass-through” to the DEVICE
port. Any data coming into the DEVICE port is sent out from the socket. Also any
data sent to this socket is sent out the DEVICE port. This type of advanced interface
is only recommended for programmers with TCP/IP socket programming
experience. The eServer listens on a predefined port number. The port number is
assigned using the setup menus. First, verify that the LISTEN-TCP option is ON.
port device,listen-tcp on
Then assign the predefined port number. For example, assume the predefined port is
3000.
port device,tcp-port 3000
The eServer acts as the “server” and listens on the predefined port number. It is up to
the developer’s custom application (acting as the “client”) to initiate the connection
to the eServer socket. For most TCP/IP socket APIs (Application Programming
Interface) the actual connection is achieved with the connect() function. This may
differ depending on which socket API is utilized. Since this is a standard TCP/IP
socket, client applications can be written on many different platforms or in different
programming languages. When the TCP socket opens, SIMPL+ (if running) pauses
until the connection is closed.
Setup Menus
The eServer is an Ethernet device that is extremely flexible in the way it can provide
Internet appliance capabilities to any RS-232 controlled device. As an Ethernet
Operations Guide - DOC. 8148 Ethernet OEM Module: eServer™ • 11