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???
03/07/07 22:31
Modified:
  03/07/07 22:46
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 		 #134551 - TxD pin to TxD pin?
Responding to: ???'s previous message
1. When i was reading a website regarding serial communication and its related signal pins, i came across this quote saying that the TxD pin of the DTE (in this case 8051) is supposed to be connected to TxD pin of the DCE (modem). This is also called as straight through cable. The question here, is why? I thought the TxD of DTE is supposed to be connected to RxD of DCE since the DCE is supposed to accept command from the DTE.


The transmit pin from the PC transmits to the "transmit" pin of the modem (but actually the modem is receiving the data from this pin so from the point of view of the modem it would be a receive pin).


This is the link to the site :

http://tldp.org/HOWTO/Serial-HOWTO-20.html


2. Also, how am i supposed to know whether the modem has successfully execute each AT Command i fed into it (before i send additional AT Command)? Is this sufficient just by looking at the TI flag everytime i send out a the last character of a command (Meaning, i am allowed to send new command once the TI flag is asserted)? Or must i wait for a status signal via CTS from the modem?


List of 72 messages in thread
TopicAuthorDate
Serial Communication Related Problem            01/01/70 00:00      
   partial answers            01/01/70 00:00      
      Oh yeah, i forgot about that            01/01/70 00:00      
   FIRST, THEN, THEN, THEN            01/01/70 00:00      
      A little bit of sarcasm as usual but often helpful            01/01/70 00:00      
         Proper baud rate...            01/01/70 00:00      
            baud rate            01/01/70 00:00      
               calculator            01/01/70 00:00      
            modem is autobauding            01/01/70 00:00      
               Noted            01/01/70 00:00      
   Some answers            01/01/70 00:00      
      Thanks for a patience reply            01/01/70 00:00      
   Nothing to add, but ...            01/01/70 00:00      
      i second(ed) that motion            01/01/70 00:00      
         My location profile?            01/01/70 00:00      
            with this known, it would do no good ...            01/01/70 00:00      
               Radio Shack            01/01/70 00:00      
                  Even so            01/01/70 00:00      
                     I can buy it from the local electronic shop            01/01/70 00:00      
            Sarcasm            01/01/70 00:00      
               I agree            01/01/70 00:00      
      Thanks for understanding and recommendation! - NT            01/01/70 00:00      
      More info            01/01/70 00:00      
         you need to understand the parameters.            01/01/70 00:00      
            "more valid" evidently means invalid            01/01/70 00:00      
            not quite            01/01/70 00:00      
               What a wonderful example that when total crap is s            01/01/70 00:00      
                  lesson            01/01/70 00:00      
            No, it doesn't            01/01/70 00:00      
   TxD pin to TxD pin?            01/01/70 00:00      
      dte-dce-dce-dte            01/01/70 00:00      
         Noted! Thanks!            01/01/70 00:00      
            same request question            01/01/70 00:00      
      Meaning of "Transmit"            01/01/70 00:00      
   same request question 2            01/01/70 00:00      
   Initial command sending code; help me take a look!            01/01/70 00:00      
      Make it simple for yourself            01/01/70 00:00      
         Why the need of circular buffer? Receiving?            01/01/70 00:00      
            polling versus interrupt            01/01/70 00:00      
               Check OK string at RXD or DCD at interupt?            01/01/70 00:00      
                  no good            01/01/70 00:00      
                     Voice mode only! No data communication.            01/01/70 00:00      
                        you are missing the basics            01/01/70 00:00      
                           NO carrier sent after DCD didn't found            01/01/70 00:00      
                              I do not agree            01/01/70 00:00      
                                 Interupt DCD signal for clear transmission            01/01/70 00:00      
                        For Voice Dialling            01/01/70 00:00      
                           and by the way            01/01/70 00:00      
                           Sorry for multiposting            01/01/70 00:00      
                           The ";" works but...            01/01/70 00:00      
                              ";" to return to idle state            01/01/70 00:00      
                              +++ with 3 seconds no modem activity            01/01/70 00:00      
                                 +++ escape sequence            01/01/70 00:00      
                                    Monkey See. Monkey Do.            01/01/70 00:00      
                                       Now monkey also understand?            01/01/70 00:00      
                                 Are you mistaken?            01/01/70 00:00      
                                    I think so            01/01/70 00:00      
            Circular buffers            01/01/70 00:00      
               Initial code for receiving modem response            01/01/70 00:00      
                  don't fiddle with the timer, let it run            01/01/70 00:00      
                     Understood, will run TR1 in global init, thx! - NT            01/01/70 00:00      
                  check this out, Eugene...            01/01/70 00:00      
                     Ah! Didn't know that! Thanks! -NT            01/01/70 00:00      
                     Code; modem commands & responses            01/01/70 00:00      
   V.250 (formerly V.25-ter) - get it free!            01/01/70 00:00      
   code,modem command and response            01/01/70 00:00      
   system froze when connected to hyperterminal            01/01/70 00:00      
      Your code...            01/01/70 00:00      
         It should not be a hardware problem since..            01/01/70 00:00      
            Not necessarily            01/01/70 00:00      
      Just taking a stab at it...            01/01/70 00:00      
         two 'ugly' guesses            01/01/70 00:00      

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