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???
12/27/07 11:33
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 		 #148783 - Still missing the point
Responding to: ???'s previous message
Ap Charles said:
PSTN modems requires -48VDC to operate they dont work on unconditioned lines?

No, they don't require it.
It's there, so they use it - but they don't require it!

And ADSL is out out my scope , it is carrier modulated over high frequency domain and needs ISP protocols to establish connections.

That's entirely irrelevant!
Again, nobody's suggesting that you implement ADSL!
We're just illustrating the fact that all these things go over very basic copper pairs - if they can be used for ADSL, they can be used for your much simpler requirement!




List of 56 messages in thread
TopicAuthorDate
Line driver IC            01/01/70 00:00      
   Telephone lines?            01/01/70 00:00      
   Slower analog solution..            01/01/70 00:00      
   That's a job for a transfomer!            01/01/70 00:00      
      line driver            01/01/70 00:00      
         Missing the point            01/01/70 00:00      
            Eh?? What is            01/01/70 00:00      
               Modem?            01/01/70 00:00      
                  Think Telco even if it's not            01/01/70 00:00      
               Have you read the datasheet?            01/01/70 00:00      
                  Not the modem speed            01/01/70 00:00      
                  What datasheet??????            01/01/70 00:00      
                     That is the datasheet            01/01/70 00:00      
                        I mentioned the chips and you say I havnt            01/01/70 00:00      
               No, you don't            01/01/70 00:00      
         Xformer only            01/01/70 00:00      
            at this low data rate (9600 bps) he could use AMI            01/01/70 00:00      
               AMI protocol            01/01/70 00:00      
                  who said anything about protocol?            01/01/70 00:00      
                     Difficult and with few software options            01/01/70 00:00      
                        Nobody said anything about a protocol            01/01/70 00:00      
                           Getting ahead of the questions            01/01/70 00:00      
                              fact is ... we don't have the information ...            01/01/70 00:00      
                                 Spare wire is already there . We do not            01/01/70 00:00      
                              Getting ahead of the questions            01/01/70 00:00      
                                 What type of wire and what environment?            01/01/70 00:00      
                                 please stop this mistreatment of a word            01/01/70 00:00      
                                    A Protocol is a set of guidelines or rules.            01/01/70 00:00      
                                    Apologies , I meant CODEC nor protocols            01/01/70 00:00      
         I am not sure...            01/01/70 00:00      
   27 or more solutions exist ...            01/01/70 00:00      
      ~9600bps            01/01/70 00:00      
         9600 is tough at that distance, so            01/01/70 00:00      
            Tough?            01/01/70 00:00      
               Not Tough? but costly.            01/01/70 00:00      
                  Still missing the point            01/01/70 00:00      
      He did specify the data rate            01/01/70 00:00      
         Where to apply modulation schemes when            01/01/70 00:00      
            Oh yes you have!            01/01/70 00:00      
            Driver/interface            01/01/70 00:00      
   no            01/01/70 00:00      
   Maxim Preemph RS-422 driver            01/01/70 00:00      
      FEET            01/01/70 00:00      
         speed and distance still apply            01/01/70 00:00      
            a pretty fancy rf link would fit the cable budget            01/01/70 00:00      
               Reverse engineer these            01/01/70 00:00      
                  Reverse engineer these            01/01/70 00:00      
                     buy one and find out            01/01/70 00:00      
                     Seems simple enough!            01/01/70 00:00      
                  Why not            01/01/70 00:00      
                     No black (box) magic methinks            01/01/70 00:00      
                        an other blackbox            01/01/70 00:00      
                           current loop vs balanced signal lines            01/01/70 00:00      
                              Have you ever heard of the teletype?            01/01/70 00:00      
                                 Bell system teletypes            01/01/70 00:00      
                              10...15years ago            01/01/70 00:00      

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