If the Port Script is edited, there may be an error in the script. There is no way for RedEye to gracefully accommodate errors, which normally involve syntax.
To help avoid scripting errors, test your code in an IDE outside of RedEye.
If the IP address or Port number is changed and saved within RedEye’s Devices Edit Port Settings, click Edit Port Script and click Apply Changes. Even if no changes are made to the script, the link between the script and port must be re-established, apparently.
If you find the RedEye isn’t as snappy as expected, try resetting it.
From the RedEye Maintenance page

1. Backup Data
2. Factory Reset
3. Restore Data

If this doesn’t seem to help…
Download the latest firmware update from ThinkFlood
From the RedEye Maintenance page

1. Backup Data (if needed)
2. Upgrade Software (using the downloaded update)
3. Restore Data (after RedEye restarts)

If RedEye continues to act-up, search the ThinkFlood Forums for advice on reseting.

To help develop error free code, use an IDE like ZeroBrane Studio. Of course, there are other options.

Try searching google for your device and ip rs232 or custom install. Here’s a list for Pioneer, Pioneer AV Receivers
And specifically for the VSX-1121-K

A block comment is fine …

--[[this is a
comment]]

… unless it contains an embedded [[...

--[[this is a
[[comment]]

... which totally whacks out RedEye.

Slider, Show value can't be set (won't stick) in web browser setup. Changes made using an IOS device do stick.

Using RedEye's

GetVariable()

always returns a string.
Convert it to a number before comparing to another number in an if statement. Example:

local c = tonumber(Scripting.GetVariable("IPmsgCount"))

If iOS stops updating variables quit and re-launch on the iGadget.

To take effect, changes to the Port Script must be saved using the Save Changes (green) button on the Devices page.

Do not send device commands from within the PortListener. It can enter an infinite loop if the sent command returns a result (always for Pioneer VSX).
Infinite loops can be terminated by editing the PortListener script and saving it to the RedEye.

There can be a device (e.g. AV Receiver) that is setup in RedEye twice. Don't use the IP address and Port combination more than once.

• Point your web browser at the RedEye.
• Click Setup
• Click the Room
• Click Custom Variables

1. Click Add New Variable
2. For Name enter myInput
3. Value can remain empty
4. Click Save

Click Add New Command

1. For Type select Other
2. For Name enter Send IP Cmd
3. Click Edit Script and go to the next step – Enter Script.
4. When the next step is complete, click OK

Replace line 5, as indicated above, with the following script .

local c = string.upper(Scripting.GetVariable("myInput"))
local b = Scripting.GetVariable("HTMLbody")
    b = [[<tr>
    <td style="border-style: none; text-align:left;">(user)</td>
      <td style="border-style: none; text-align:left;">]]
        .. c .. " -----" ..
      [[</td>
    </tr>]] .. b
Scripting.SetVariable("HTMLbody", b)
Scripting.SetVariable("HTMLmsg", [[<table style="font-size: 80%;">]] .. b .. [[</table>]])
Scripting.SendMessage(c.."\r")

Click Apply Changes
Complete step 4 of the previous step.

1. Click Save Changes
2. Click Layout > Edit

1. Click on HTML field to highlight
2. Click and drag to make room at the top

1. Select Text Field
2. Click Add Control
3. Position new Text Field

1. Click to highlight Text Field
2. Click Text Field Values
3. Select Text Variable, myInput

1. Select Button
2. Click Add Control
3. Drag to reposition button

1. Select button
2. Click Actions / Toggles
3. Select Type as Normal
4. Select Action Type as Command
5. Select VSX A/V Receiver (your device)
6. Select Send IP Cmd
7. Click green, Save Changes button

Return to Devices page and click (Exit)
Select the device (VSX A/V Receiver)

1. Enter a command
2. Click outside of the text box (so the entered text is stored in the System Variable)
3. Click Send IP Cmd

After a short delay, the sent command should display, followed by the response sent by the VSX.

• Point your web browser at the RedEye.
• Click Setup
• Click the Room
• Click Custom Variables

1. Click Add New Variable
2. For Name enter IPmsgCount
3. Value can remain empty
4. Click Save
5. Repeat for variable HTMLbody
6. REpeat for variable HTMLmsg

From the RedEye Room, click Devices
Select your device.
Click Edit Port Script

Add the following functions to the Port Script as indicated:

function string:split(sep) -- split (parse) string --> table
    local sep, fields = sep or ":", {}
    local pattern = string.format("([^%s]+)", sep)
    self:gsub(pattern, function(c) fields[#fields+1] = c end)
    return fields
end

function buildHTML(ipMsg)
    local c = tonumber(Scripting.GetVariable("IPmsgCount"))
    local b = Scripting.GetVariable("HTMLbody")
    if c > 90 then
        c = 0
        b = ""
    end
    c = c + 1
    b = [[<tr>
      <td style="border-style: none; text-align:left;">]]
        .. c .. "/" .. #ipMsg ..
      [[</td>
      <td style="border-style: none; text-align:left;">]]
        .. table.concat(ipMsg,"<br>") ..
      [[</td>
    </tr>]] .. b

    Scripting.SetVariable("IPmsgCount", c)
    Scripting.SetVariable("HTMLbody", b)
    return 
[[<table style="font-size: 80%;">]]
    .. b ..
[[</table>]]
end

Click Apply Changes

Add the following to the Port Script as indicated.

    local t = inputData:split("\r\n") -- store message elements in table "t"
    Scripting.SetVariable("HTMLmsg", buildHTML(t))

Click Apply Changes

At this point, the Port Script will accumulate all messages received from the VSX and store it in the State Variable named HTMLmsg.
Building the html code in this way, isn’t very efficient. Using a table would no doubt improve the speed.
All that remains is to display the HTML.

Return to the VSX device page.
Click Layout Edit

The default buttons won’t be use right now, so they may be deleted or moved down the layout to make room.

1. Select HTML
2. Click Add Control

1. Click the HTML control in the Layout (indicated by the yellow #1 and blue line)
2. Within the Device Remote Layout > HTML Values > HTML Content Variable, select the variable HTMLmsg
3. Click Save Changes
4. Return the the Devices page and click Save Changes
5. Click (Exit) to return to the RedEye home screen

From the RedEye home page:

• Click Devices
• Click the device VSX A/V Receiver

The control pane should appears as shown above.

1. The left column indicates: message number / number of distinct elements in this message
2. The right column shows the list of messages.

When the number of received messages exceeds 90, the storage variable (HTMLbody) is cleared. See line 16 of the final script.
As shown in the screen shot, there are frequently multiple elements in any given message. This explains why control is unreliable when this fact is ignored.

1. Select the desired Manufacturer
2. And Type
3. Change the Port to Add New IP Port
4. Enter your desired Display Name
5. Click Find Codes

At the time of this tutorial, there was just a single codeset for the VSX. It doesn’t quite match the VSX-1121-K, but the commands can be edited later as needed.
If you device doesn’t have a codeset, save the device without.

1. Click the Codeset desired
2. Click Save This Device

1. Click Edit Port Settings

1. Ensure the Protocol is set to TCP
2. Enter the IP address as the Host Name
3. Enter the Port Number
4. Click OK

With your VSX reveiver turned on, test the IP control from RedEye.

1. Click Mute On/OFF
2. Click Save Changes

Launch AirPort Utility 5.x.

1. Select your router.
2. Click Manual Setup

Click Internet.

Click DHCP.

Click plus to add a DHCP Reservation.

1. Enter a Description.
2. Ensure that MAC Address is selected
3. Click Continue.

1. Enter your client’s MAC Address.
2. Enter your desired IPv4 Address.
3. Click Done.

1. Your newly added IP client will be in the DHCP Reservations list.
2. Click Update. The router will go off-line for a minute or so while it saves your changes.

The router’s icon will disappear while being updated. Quit AirPort Utility.

Launch AirPort Utility 6.x.

1. Click your router.
2. Click Edit.

Click Network.

Click plus to add a DHCP Reservation.

1. Enter a Description.
2. Ensure that MAC Address is selected
3. Enter your client’s MAC Address.
4. Enter your desired IPv4 Address.
5. Click Save.

1. Your newly added IP client will be in the DHCP Reservations list.
2. Click Update. The router will go off-line for a minute or so while it saves your changes.

1. Press RECEIVER.
2. Press HOME MENU.

Down-arrow to 4. System Setup
Press ENTER

Down-arrow to d. Network Setup
Press ENTER

Down-arrow to 2. Network Standby
Press ENTER

Use right-arrow to turn on Network Standby
Press RETURN

Down-arrow to 5. Port Number Setting
Press ENTER

Use default port (23) or add your own. In either case, record the value. Port values can be from 1 to 65535.
Down-arrow to OK
Press ENTER
When asked to accept and save changes:
Arrow to Yes
Press ENTER
Wait a minute or so for changes to be set.
Press RETURN twice, to return to the HOME MENU screen.

Down-arrow to 5. Network Information
Press ENTER

Record the MAC Address.
Press HOME MENU to exit.
You’re done!