Dear Team,
 
We are trying to send simple RS-232 commands to a Cisco LCD connected via serial cable to a DMP-4400. We have written a simple JavaScript class that sets the MIB keys on the DMP using the XMLHttpRequest object. Our approach is to set the values of the following MIB properties on the DMP to send the RS232 commands.
 
rs232.tx_hex T_STRING
rs232.tx_str T_STRING
 
We build a URL string as follows and use the XMLHttpRequest object to send the commands to the DMP. The XMLHttpRequest also includes the Basic Authorization header with the DMP's Web Access credentials encoded in Base-64 (username:password). We have tested that the XMLHttpRequest is successfull to send other DMP commands such as to restart the DMP or browse to a website.
 
http://[DMP IP]:7777/set_param?rs232.tx_hex=aa11fe010010
 
However, we are unsuccessful when trying to send RS-232 commands. There is no response on the screen. We have even tried to hookup the serial cable to a PC and monitor the serial output on HyperTerminal when we send the commands. This also returned no results.
 
Is there any additional settings that we need to do on the DMP to enable RS-232 communication on the DMP?
 
Your team's response is greatly appreciated.

 
Hi Gregory,
 
We've enabled the RS-232 port as you've mentioned. The only difference is that on our DMP the RS232 device is on ttyS0 and not ttyS1 as you've mentioned.
 
rs232.device T_STRING /dev/ttyS0
 
We've tried changing it but it doest change. Does this affect it in any way? The RS-232 commands still does not work.
 
I've attached a copy of our DMP MIB settings.

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