How To - Telnet Interfaces (Devices)

The OpenRemote 2.0 controller has the option to control a variety of devices via the telnet protocol. This how-to will explain in detail how you can implement different actions like:

• Sending single commands
• Receiving and using status messages
• Extract status messages via Java regex (regular expressions)

This implementation is still in a development phase so the way different objects are handled can change in the course of time.

Different Types of Telnet Implementation

The telnet protocol can be implemented in a few different varieties. OpenRemote will support the CF and non-CF type connections. What this effectively means is that the telnet connection is able to directly send commands to the target with or without receiving a control prompt.

Example with CF (without control prompt):

$ telnet 192.168.10.110 7072
Trying 192.168.10.110...
Connected to 192.168.10.110.
Escape character is '^]'.

$ telnet 192.168.10.110 7072
Trying 192.168.10.110...
Connected to 192.168.10.110.
Escape character is '^]'.
prompt>

How do I know what kind of target I have?

Execute:

$ telnet <target ip> <port>

When you receive a message like the one below you have a target WITHOUT a control prompt.

Trying <target ip>...
Connected to <target ip>.
Escape character is '^]'.

Adding Telnet Commands in Designer and Adding a New Device

In the example shown a basic ON/OFF switch is created with a feedback sensor.

Logon to the Online Composer

1. Add a new Device

Add a new device by clicking the menu Devices --> New --> Device.
The "Vendor" and "Model" are dummy parameters and are only meant for administrative purposes.

2. Add an ON command

Now add 3 new commands by selecting the newly created device and click New --> New Command.
In this example an "on" command is sent to the target.
If your telnet target has a control prompt, the parameter below can be discarded.

The correct sequence should be: <null><pipe><command>
No spaces are allowed.

null|

Click "Submit and Continue" to add a new command without loss of parameters.

3. Add an OFF command

Change only the "Name" and the "Command" itself

Click "Submit and Continue" to add a new command without loss of parameters.

4. Add a status feedback command (boolean of regular expression style)

For a switch sensor to work correctly a boolean "on" or "off" responds is required. The following 2 examples will show how these can be obtained in different ways.

4. 1. Add a status feedback command (boolean)

Sending the command:

null|{ $value{Stalamp_KL}}

4. 2. Add a status feedback command with regular expression (regex)

Not all devices have direct command which will show the status of the device. Handy enough we included a regular expression match to get the specific info needed. The chosen method is not the easiest, but it is the most flexible.

Parsing the command:

null|list Stalamp_KL

Internals:
   BTN        03
   DEF        2611 03
   IODev      CUNO1
   NAME       Stalamp_KL
   NR         19
   STATE      on
   TYPE       FS20
   XMIT       2611
   Code:
     1          2611 03
   Readings:
     2011-02-13 17:39:25   state           on
Attributes:
   loglevel   5
   model      fs20di
   room       Huiskamer

The regular expression needed to extract "on" from the total out put looks like:

^(?i)(?s)(?m).*STATE\s+(\w+).*$

Surf to Regular Expression Testing

• Enter the regular expression in the "Regular Expression" field
• Enter the (to be parsed) output in Testfield #1
• Ensure CANON_EQ and UNICODE_CASE are checked

Hit "Test" and the outcome will appear.
You will see that the box "group(1)" will contain the value "on". This is a correct boolean outcome.

Easy as that *kuch*

Sensors

Sensors in Openremote are used for relaying status data directly to the GUI frontend or for capturing different events. They rely per basis on a correct command which has been discusses in part 4.1.1

1. Add a switch sensor

Add a new switch sensor by selecting the "Device" -> New -> Sensor
Select the correct command for requesting the status and select "Switch" as the sensor type.

Switches

Switches in Openremote come only in a single type: ON/OFF

1. Adding a Switch

Add a new switch by selecting the "Device" -> New -> Switch
Select the correct switch sensor, on and off commands.

Final configuration

The content of your device should look like the model below now.

If you miss any components please go back and retrace your steps to see where you went wrong.
All the components should be there to display a correct function!