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Mahmood Elnasser
02/10/12 14:24
  02/10/12 14:33

Read: 464 times

#185827 - details
Responding to: Kai Klaas's previous message
I have a project to control relays 3km away and send audio one way for a distance of 3km+ for a local factory.
The status of relays should be sent back to the operator's control panel for monitoring.
However land phone lines are available between operator and distination on a local exchange(free).
I was investigating many methods of doing it, but since phone lines are available, I thought using the phone lines for both voice and DTMF signaling would be most suitable.
I'm also making a control panel for operator, thinking of adding a touch screen for operator with color LCD, maybe an industrial computer with a touch screen. or is it overkill for a simple operation? why not just use switches and LEDs?

List of 12 messages in thread
long range RS-485      Mahmood Elnasser      02/10/12 01:51      
   Current loop?      Per Westermark      02/10/12 02:29      
   Repeaters?      Daniel Contarino      02/10/12 06:10      
   can you use repeaters?      Erik Malund      02/10/12 07:58      
      No      Mahmood Elnasser      02/10/12 14:10      
   Profibus people...      Kai Klaas      02/10/12 08:03      
      details      Mahmood Elnasser      02/10/12 14:24      
         just a note      Erik Malund      02/10/12 17:04      
         Phone lines...      Kai Klaas      02/10/12 17:06      
            phone lines      Mahmood Elnasser      02/10/12 23:06      
               Data collision      Kai Klaas      02/11/12 05:35      
   It just works at slow speeds      Oliver Sedlacek      02/14/12 05:03      

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