Communicating with ethernet to serial LED sign - is this feasible?

windswept321 · January 7, 2020, 6:45pm

I have a london-electronics LED sign I picked up on eBay which I would like to display custom messages on programmatically. It is working ok.
Opening it up, it has an ethernet to serial connection currently plugged in and a serial connection currently unplugged internally (same connectors). Ideally, I would like to communicate with it over ethernet to save plugging a computer into it directly.

The manufacturer kindly provided me with some links detailing serial communication with the LED sign.

Is it feasible to communicate with it over ethernet without using their windows software? If so, how can I send serial commands over ethernet?

jgt · January 7, 2020, 9:02pm

I think that all you need to do is use netcat.

echo "some message" |netcat -h led_ip_address -p port_number

Port number should be in the LED sign documentation.

windswept321 · January 8, 2020, 11:31am

Thanks for responding.
I am currently testing in OS X so have modified the command a little.

As per the attached images, this command should clear the display:

\x02F901600001\x03

F9...01...60 is where the device address is entered. I tried setting this to 00 which I think should be the broadcast address. However, nothing happens to the display - it continues to run through what looks like a demo program.

I don't know the device address and can't see any means of finding it out from the windows configuration / management software. It gave me the correct IP address and port which netcat confirms is open.

I have been testing like this but nothing happens to the display:

echo -e �\x02F900600001\x03� | nc 192.168.0.188 1001

Command info:

jgt · January 8, 2020, 12:07pm

Device address probably should be one, not zero.

The concept of device address stems from RS485 serial communications that allow for daisy chained devices.

Are there possibly dip switches or a ROM config process to set the device address?

windswept321 · January 8, 2020, 12:21pm

1 doesn't work either. I was going by the screenshots I tried to share but I don't think they went up.
I have attached them to this post.

hicksd8 · January 8, 2020, 1:55pm

Does the ethernet to serial adapter have a brand name on it? Often these devices are oem'd from a third party that manufactures the adapters. Also, they are often configured on the LAN using a browser. If you know the ip address of the adapter have you tried putting that address into a browser to see if you get invited to configure the thing?

To answer your first question, yes, it is certainly possible to access a serial device over ethernet using an adapter.

e.g.
NETRS232485 | Startech RS232 to Ethernet Ethernet Adapter | RS Components

jgt · January 8, 2020, 2:05pm

Download digital panel meter and large display technical data, forms and brochures

I presume this is the hardware

windswept321 · January 8, 2020, 5:35pm

This is the ethernet to serial adapter - Tibbo branded. I was able to communicate with it using their Windows software.

windswept321 · January 8, 2020, 5:42pm

This is the hardware. It loops through the same messages shown on the signs on the table in the bottom photograph.

hicksd8 · January 9, 2020, 9:58am

If you can unplug the ethernet-RS232 adapter from the display I think I'd be inclined to test the ethernet-RS232 adapter by shorting pins 2 & 3 (is this a DB9 or a DB25 connector) to loop back any received characters, make a connection over ethernet and see if the adapter echos the characters typed. Also, directly connect a laptop to the serial input of the display (using an old laptop with a DB9 serial connector or a USB-serial adapter) and see if you can control the display using the commands given.

Once both of those tests are done reconnect the ethernet-RS232 adapter to the display. Remember to also consider baud rates, 8 bit or 7 bit, stop bits, and parity/no parity which could also cause it not to work until they are aligned.