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Serial RS232 Troubleshooting

In order for a control system to send serial commands to a Just Add Power device for endpoint control, these things must be correct (ordered from most common resolution to least common resolution):


Static Route enabled

Any form of endpoint control - including serial - requires the use of a Static Route. It enables a device on the local data network to communicate to the Just Add Power devices on their individual subnets within the switch.

When JADConfig finishes it provides a JADConfig Report file that describes all of the device settings in the system. The Report file has the information needed to create the Static Route.

Enable

To enable the Static Route, login to the router in the system and enter the information from the JADConfig Report file. It is typically in a section labeled Routing or Advanced.

Static Route

Confirm

The Static Route is enabled when a PC on the network can open a web interface to the IP of a Just Add Power device.


 Null Modem Jumper

All Just Add Power devices with a 3.5mm port for RS232 also have a null modem jumper. On the bottom of the device there are two black jumpers that connect two pins together. The TX and RX pins on the RS232 cable depend on the jumper positioning.

Enable

Null modem top position     Null modem bottom position

The jumper position closest to the serial port (left picture above) is for a straight-through serial cable. This is the correct pinout for most serial-controlled endpoint devices.

The jumper position furthest from the serial port (right picture above) is for a crossover serial cable or for connecting to the Flux Capacitor IR Dongle v1 or v2.

The correct pinout always depends on the pinout of the endpoint device.

Confirm

Attempt to send the command. If it doesn't work, move the null modem jumper to the other position and send again. If all other parts are correct, one of the positionings will work.

As the null modem jumper is one piece among many in the line of physical connectivity, the only way to 100% confirm is to successfully send a command or to read the command coming out of the Just Add Power device. To do this in the most reliable way, connect the RS232 port of the Just Add Power device to a USB-to-serial adapter into a PC running PuTTY or Docklight Scripting. Send the serial command and use the PC to monitor the commands coming out of the Receiver. If the commands come through, then the line of physical connectivity - including the null modem jumper - are correct.

Monitoring RS232 with a PC


Serial Code and Format

Serial codes are manufacturer-specific. Furthermore, some manufacturers have more than one set of codes that are used for different types of devices - for example, Samsung standalone displays use different codes than Samsung video wall displays.

There are two ways to send codes: ASCII or hex. The format of the code affects how it must be formatted to be sent correctly.

ASCII represents keyboard characters and can be typed as written with no special formatting.

Hex uses pairs of 0-F computer code and must be formatted by preceding each hex pair with a special character - \x for Just Add Power, but will depend on the control system being used. For example, if the hex code 08 22 00 00 00 01 D4 needs to be sent, then the correct formatting is:

\x08\x22\x00\x00\x00\x01\xD4

Enable

If the code is ASCII, type it exactly as written.

If the code is hex, format it with the appropriate special character.

Confirm

Aside from referencing the manual to find the correct code and format, the only way to confirm is to send the code and have it work.

The only way to 100% confirm is to successfully send the command or to read the command coming out of the Just Add Power device. To do this in the most reliable way, connect the RS232 port of the Just Add Power device to a USB-to-serial adapter into a PC running PuTTY or Docklight Scripting. Send the serial command and use the PC to monitor the commands coming out of the Receiver. If the commands come through as expected, then the code is entered correctly. If the endpoint device still doesn't respond to the code, then the code is most likely wrong.

Monitoring RS232 with a PC


Just Add Power device IP

Serial commands are sent based on the IP of the Just Add Power device that is connected to the endpoint.

Confirm

Rebooting the Just Add Power device via telnet or the web interface and then looking for the hardware to reboot will confirm that the correct device is being controlled.


Set Serial Type and Baud Rate

Just Add Power supports 3 different operational methods - referred to as Types:

  • Type 1 Dumb Redirection - RS232 port on the Transmitter and RS232 port on the Receiver are linked together
  • Type 2 Guest Mode - RS232 port access via telnet to port 6752
  • Type 3 CLI Access - RS232 port access via telnet to command line interface at port 23 and using 'printf' functions

Full information on each Type can be found in the main RS232 article.

Enable

If using the Just Add Power driver for AMX, Control4, Crestron, or RTI then the device is already in the correct Type.

To set manually, log into the web interface of the device and go to the Functions tab. Scroll down to the Serial over IP section, select the right Type and enter the baud rate, and click Apply. Reboot the unit to apply the settings.

Confirm

The web interface of the device will list the current serial Type and baud rate. Go to the Functions tab and scroll down to the Serial over IP section.

Serial over IP web interface


Physical Cabling

When all other options have been exhausted, the only remaining possibility is the wiring between the Just Add Power device and the endpoint device.

Test

To check a physical cabling problem a hardware swap must be done.

  1. Swap the RS232 cable
  2. Swap the Just Add Power device with another known-working device
  3. Swap the endpoint device or connect the Just Add Power device to a different endpoint device.

Confirm

As with any physical connectivity issues, the only way to 100% confirm is to successfully send the command or to read the command coming out of the Just Add Power device. To do this in the most reliable way, connect the RS232 port of the Just Add Power device to a USB-to-serial adapter into a PC running PuTTY or Docklight Scripting. Send the serial command and use the PC to monitor the commands coming out of the Receiver. If the commands come through as expected, then the code is entered correctly. If the endpoint device still doesn't respond to the code, then the code is most likely wrong.

Monitoring RS232 with a PC

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  • 02-Jan-2020
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