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LED SIGN COMMUNICATION PROTOCOL

aj85
aj85 used Ask the Experts™
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I have an application that I need to create to connect and send commands to an outdoor led sign.  The problem is not connecting to sign, but the communications protocol commands that tell the sign to scroll, what text to display etc..  I have a few known commands for this type of sign, however the problem is that there are several commands that are not very clear to me.  

One specific issue is the font type and size command, in the booklet attached it indicates that the command for fonts is "FT" with a default type of 2.  However I am not sure what font type that is, or how to change it to Arial with a pitch of 10 or San Serif with a pitch of 10 for example.  My question is are there standard protocol commands that are used by led sign displays?  If so what are the font commands to change the type etc.?  The signs came from a company called Mega Signs, however it seems that they are just the sales agent company as they do not have technical support: http://www.megasigninc.com/.

Thanks,
aj85
COMMUNICATIONS-PROTOCOL.pdf
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Commented:
if you are connecting via serial cable with hyperterm or a telnet session  try typing "?" or "help"

Author

Commented:
Hello, I am connecting via bluetooth and a COM port.

aj85

Commented:
aj85, the COM port, is that a 9pin or 25 pin male connection? if it is you can connect and run
a telnet. if telnet answers you are in the operating system, you can type "help" or "?" or you may displayed a menu system.  if the sign is installed already, serial cables can run like 10-20'

if you connect via bluetooth, there's a windows application that you interface with to change your signage.

Author

Commented:
Hello,

The connection is via this bluetooth antenna: www.sena.com UD100.  There is an application that came with the sign, however it was insufficient and was bulky.  So I managed to get the communication protocol and design an interface to connect and send messages to the sign.  The issue is that I do not know what the commands are to control the font size.  If you saying that I can somehow connect via my interface or the one that came with the sign, and request type help to get the core commands, I am willing to try this immediately..... :-)  Just give me the step to implement this as I am not sure where to turn on using telnet.

Thanks,
aj85
cup

Commented:
I'm just assuming you're using Windows.  Apologies if you're using Linux.

On Windows, pop up a cmd prompt.  For help on parameters type

telnet /?

Telnet is an internet utility.  By default, it connects on port 23 to the ipaddress specified.  If you don't have an ipaddress, it probably won't work.  It will not work through a serial port but it may work through blue tooth if you can establish what the blue tooth IP address is.

If it is a serial port, and you are on Win 95/98/XP, there is an app called hyperterm (as suggested by cfgtechs) in Accessories/Communications.  It doesn't exist on later versions of Windows.  Just start it up and tell it which com port you wish to connect to.

Author

Commented:
Hello cup,

Yes, I am using Win 7 Pro, however I do not know the IP address of the bluetooth device, only the COM port in which it is connected.

Commented:
sorry, cup is right about telnet. assuming your device has an IP you hook into it thru a cross over ethernet cable or via a hub/switch.

there's free hyperterminal apps for win7/vista, just plug into the com port and see if you get
a display echoing back.

Commented:
aj85, do you have a physical com port on your sign? db9, db25 pin male port shaped like a D. or is bluetooth hooking up as a com port connection? -give a hyperterminal program a try if windows see's your device as a com port, just try connecting to every com port the application sees and see if you get garbage echoing back. if you do get garbage, reboot your sign and you may see the startup

Author

Commented:
Thanks for the reply, however I think I am little confused.  These are wireless devices that I can pair with, but there is not hub, or at least I do not think so that I can connect to with a crossover cable.  I have a wireless bluetooth antenna that gets paired with the sign, but that is the only connection to it.  Is it possible to connect using hyperterminal as you outlined if I do not know the IP but only the COM port?
Commented:
aj85, disregard all that about IP. if your bluetooth link comes across as a com port to windows, yes, give a hyperterminal application a try. the hyperterm will see any comports available, should be 2-3 and test if you can connect.

Author

Commented:
Okay great I will try this approach and get back to you.  Thanks!

Author

Commented:
Hello cfgtechs,

Unfortunately this did not work either.  I connected via a program call PUTTY, and typed "help" and "?" and nothing was returned.  Not sure where to turn from here.  

Thanks,
aj85
Commented:
Looks like you need  a blue tooth packet sniffer.  Try the stuff on http://bluetooth-sniffer-device.winsite.com/

It is a full blown protocol so you're not going to get any joy with hyperterm.  What you can do is look at the packets when you're connected and tie up the commands you're sending with what is in the packets and probably work out what your font size command is.

Author

Commented:
Hello,

Okay I will try this and get back to you.  Thanks.

aj85