Filter
Top Products
IPL T SF24 and IPL T SFI244 • Communication and Control
IPL T SF24 and IPL T SFI244 • Communication and Control
Communication and Control, cont’d
Figure 4-23 — Example of SSI “remote” command
In figure 4-23 above, a “remote” serial command sends the
word “hello” and will wait up to 50ms for a response (until
three characters are received). For more information on this
command, refer to the Command/response table for Simple
Instruction Set (SIS) commands earlier in this chapter.
Query string
A query string is the portion of a URL that appears after the
question mark. The query string contains parameters or
instructions for the Web server to execute.
The basic format for a query string within a link is:
<a href=”index.html?cmd=x”>Input #1</a>
Where x is the SIS command to be executed.
When a link is accessed on a Web page, the URL is passed to the
Web server to tell it which Web page to return to the browser.
The portion of the URL after the question mark is the query
string, which contains the SIS command that the IP Link
product will remove and execute.
As with SSI formatted commands, query strings can use any
valid SIS command—either “host” or “remote”.
The query string in figure 4-24 below will turn off DHCP on the
IP Link device.
Figure 4-24 — Example of a host query
string command
<a href="index.html ?
Starts
Query String
SIS Command
URL with a Query String using a Remote SIS command
*type with no spaces
Tells web server
the an SIS follows
HTML code
for a link
cmd=
Closes
Link
</a>
HTML code
for a link
">
Linked Text
Input #1
W
Delimiter
Port
Number
2
Command
RS
Delimiter
1!
Data to be passed to
external device
via a serial port
<html>
<head><title>Example 1</title></head>
<h2 b>HTML Example #1</h2 b>
<body>
The following lines demonstrate how to read status from the IPLink Product:
<p>
IPLink Product Name: <b><!--#echo var="1I"--></b>
<br>
IPLink Product Description: <b><!--#echo var="2I"--></b>
<br>
IPLink Product Part Number: <b><!--#echo var="N"--></b>
<br><hr>
<p>
This example requires an Extron Crosspoint 84HVA connected to IPL T SF244
serial
port #1.
<p>
Part Number: <b><!--#echo var="W01RS|N"--></b>
<br>
Connection Info: <b><!--#echo var="W01RS|I"--></b>
<br>
Firmware Version: <b><!--#echo var="W01RS|Q"--></b>
"host" SSI
commands
"remote" SSI
commands
<!--#echo var=" "-->W
Delimiter
Delimiter
SIS Command
Server Side Include Using a Remote SIS command
*type with no spaces
Port
Number
1* * *
Time to wait
for first character
of response
5
Time between
characters
in response
3
Command
RS
Length or
Delimiter
parameter
3L
SIS Command
Elements
Hello
Data to be passed to
external device
via a serial port
<a href="index.html ?
Starts
Query String
SIS Command
URL with a Query String using a Host SIS command
*type with no spaces
Tells web server
the an SIS follows
HTML code
for a link
cmd=
SIS command
to be processed
by the IP Link
W0DH|
Closes
Link
</a>
HTML code
for a link
">
Linked Text
DHCP off
4-314-30
Figure 4-25 — Example of a remote query string
command
In figure 4-25 above, the data string that follows the pipe
(
)
symbol will be sent to the attached controlled device on serial
port #2. This string will instruct an attached Extron switcher to
change to input #1.
Code examples
This section shows practical uses for both SSIs and query
strings.
Before attempting to develop new Web pages, the user
should have a good, working knowledge of JavaScript,
HTML, and server side includes.
Example 1
In figure 4-26a, both host SSI and remote SSI commands are
used within the same Web page. You will notice six SSIs: three
host commands and three remote commands.
Figure 4-26a — HTML source code document
showing server side includes