Can a MAX232 IC be used for RS-232C standard?












4












$begingroup$


I have a GT01 Panasonic LCD which it's interface is RS-232C.



I have read that the difference between RS-232 and RS-232C is their voltage level which it's ±5 V in RS232C.



Can I use a MAX232 IC to communicate with this LCD?



I'm worried that MAX232'c Voltage level (±25 V) harms the LCD.



If not, would you please propose an IC which is capable with RS-232C?










share|improve this question











$endgroup$

















    4












    $begingroup$


    I have a GT01 Panasonic LCD which it's interface is RS-232C.



    I have read that the difference between RS-232 and RS-232C is their voltage level which it's ±5 V in RS232C.



    Can I use a MAX232 IC to communicate with this LCD?



    I'm worried that MAX232'c Voltage level (±25 V) harms the LCD.



    If not, would you please propose an IC which is capable with RS-232C?










    share|improve this question











    $endgroup$















      4












      4








      4


      0



      $begingroup$


      I have a GT01 Panasonic LCD which it's interface is RS-232C.



      I have read that the difference between RS-232 and RS-232C is their voltage level which it's ±5 V in RS232C.



      Can I use a MAX232 IC to communicate with this LCD?



      I'm worried that MAX232'c Voltage level (±25 V) harms the LCD.



      If not, would you please propose an IC which is capable with RS-232C?










      share|improve this question











      $endgroup$




      I have a GT01 Panasonic LCD which it's interface is RS-232C.



      I have read that the difference between RS-232 and RS-232C is their voltage level which it's ±5 V in RS232C.



      Can I use a MAX232 IC to communicate with this LCD?



      I'm worried that MAX232'c Voltage level (±25 V) harms the LCD.



      If not, would you please propose an IC which is capable with RS-232C?







      lcd rs232 max232






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Dec 8 '18 at 11:37









      Michel Keijzers

      6,02192764




      6,02192764










      asked Dec 8 '18 at 6:55









      NimaNima

      405




      405






















          2 Answers
          2






          active

          oldest

          votes


















          7












          $begingroup$

          The "C" is a 1969 Specification Revision.
          It does not dictate 25V but is compatible with that.



          Today the Spec is Ref F to expand speed, timing and low voltage enhancements and is backwards compatible.



          The standard has not changed with a threshold that is the same as TTL or 1.3V = Vbe*2 but all receivers handle a wide range of Tx bipolar voltages.




          Can I use a MAX232 IC to communicate with this LCD?




          Yes.






          share|improve this answer











          $endgroup$





















            4












            $begingroup$

            enter image description here



            Figure 1. An oscilloscope trace of a byte transmitted by an RS232 link. Source: Wikipedia RS-232.



            Note a few things:




            1. Logic is inverted. A '1' is a negative voltage and a '0' is a positive voltage.

            2. The grey area shows the valid logic level voltages. It is > 3 V for a '0' and < -3 V for a '1'.



            I'm worried that MAX232'c Voltage level (±25) harms the LCD?





            1. The purpose of the MAX232 is to convert from the RS232 signal levels to the 5 V logic levels of your circuit. It is, in effect, a buffer between the two. Your LCD will never see the ±25 V.

            2. ±25 V was used to transmit over long distances at low baud rates. These days we're typically running at 9600 baud which has a limit of 15 m or so before cable capacitance becomes a problem. As a result we don't need the high voltages and if you check with a multimeter you'll find that you'll only see about ±5 to ±7 V on most devices. The reason? They're probably using the MAX232 as well.


            You'll be fine if you follow the MAX232 recommended circuit and don't skip any of the decoupling capacitors, etc., recommended in their layouts.






            share|improve this answer









            $endgroup$













            • $begingroup$
              You missed the point here. The question was if the RS232C input can handle RS232 levels. It was not about the LCD screen itself, he was asking about the LCD module if it can be damaged.
              $endgroup$
              – Dorian
              Dec 8 '18 at 11:42










            • $begingroup$
              Thanks, @Dorian. I understood the question and I thought I had addressed it with my paragraph including "Your LCD will never see the ±25 V." In almost 40 years working with all sorts of industrial RS232 interfaces I've never seen more than 12 V and that was in the days when devices had +/-12 V supplies. Most of my answer was giving background to the protocol and the buffering as there seemed to be some confusion there.
              $endgroup$
              – Transistor
              Dec 8 '18 at 15:36










            • $begingroup$
              I know that what is missing in your answer ( +-30V ipuut range for MAX232C) is in the tatasheet that OP has read but I would had a fortune if I had a penny for each call asking for something that is in the product datasheet. Make a small edit to take back my downvote.
              $endgroup$
              – Dorian
              Dec 9 '18 at 13:02











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            2 Answers
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            2 Answers
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            7












            $begingroup$

            The "C" is a 1969 Specification Revision.
            It does not dictate 25V but is compatible with that.



            Today the Spec is Ref F to expand speed, timing and low voltage enhancements and is backwards compatible.



            The standard has not changed with a threshold that is the same as TTL or 1.3V = Vbe*2 but all receivers handle a wide range of Tx bipolar voltages.




            Can I use a MAX232 IC to communicate with this LCD?




            Yes.






            share|improve this answer











            $endgroup$


















              7












              $begingroup$

              The "C" is a 1969 Specification Revision.
              It does not dictate 25V but is compatible with that.



              Today the Spec is Ref F to expand speed, timing and low voltage enhancements and is backwards compatible.



              The standard has not changed with a threshold that is the same as TTL or 1.3V = Vbe*2 but all receivers handle a wide range of Tx bipolar voltages.




              Can I use a MAX232 IC to communicate with this LCD?




              Yes.






              share|improve this answer











              $endgroup$
















                7












                7








                7





                $begingroup$

                The "C" is a 1969 Specification Revision.
                It does not dictate 25V but is compatible with that.



                Today the Spec is Ref F to expand speed, timing and low voltage enhancements and is backwards compatible.



                The standard has not changed with a threshold that is the same as TTL or 1.3V = Vbe*2 but all receivers handle a wide range of Tx bipolar voltages.




                Can I use a MAX232 IC to communicate with this LCD?




                Yes.






                share|improve this answer











                $endgroup$



                The "C" is a 1969 Specification Revision.
                It does not dictate 25V but is compatible with that.



                Today the Spec is Ref F to expand speed, timing and low voltage enhancements and is backwards compatible.



                The standard has not changed with a threshold that is the same as TTL or 1.3V = Vbe*2 but all receivers handle a wide range of Tx bipolar voltages.




                Can I use a MAX232 IC to communicate with this LCD?




                Yes.







                share|improve this answer














                share|improve this answer



                share|improve this answer








                edited Dec 8 '18 at 20:37

























                answered Dec 8 '18 at 8:17









                Sunnyskyguy EE75Sunnyskyguy EE75

                66k22396




                66k22396

























                    4












                    $begingroup$

                    enter image description here



                    Figure 1. An oscilloscope trace of a byte transmitted by an RS232 link. Source: Wikipedia RS-232.



                    Note a few things:




                    1. Logic is inverted. A '1' is a negative voltage and a '0' is a positive voltage.

                    2. The grey area shows the valid logic level voltages. It is > 3 V for a '0' and < -3 V for a '1'.



                    I'm worried that MAX232'c Voltage level (±25) harms the LCD?





                    1. The purpose of the MAX232 is to convert from the RS232 signal levels to the 5 V logic levels of your circuit. It is, in effect, a buffer between the two. Your LCD will never see the ±25 V.

                    2. ±25 V was used to transmit over long distances at low baud rates. These days we're typically running at 9600 baud which has a limit of 15 m or so before cable capacitance becomes a problem. As a result we don't need the high voltages and if you check with a multimeter you'll find that you'll only see about ±5 to ±7 V on most devices. The reason? They're probably using the MAX232 as well.


                    You'll be fine if you follow the MAX232 recommended circuit and don't skip any of the decoupling capacitors, etc., recommended in their layouts.






                    share|improve this answer









                    $endgroup$













                    • $begingroup$
                      You missed the point here. The question was if the RS232C input can handle RS232 levels. It was not about the LCD screen itself, he was asking about the LCD module if it can be damaged.
                      $endgroup$
                      – Dorian
                      Dec 8 '18 at 11:42










                    • $begingroup$
                      Thanks, @Dorian. I understood the question and I thought I had addressed it with my paragraph including "Your LCD will never see the ±25 V." In almost 40 years working with all sorts of industrial RS232 interfaces I've never seen more than 12 V and that was in the days when devices had +/-12 V supplies. Most of my answer was giving background to the protocol and the buffering as there seemed to be some confusion there.
                      $endgroup$
                      – Transistor
                      Dec 8 '18 at 15:36










                    • $begingroup$
                      I know that what is missing in your answer ( +-30V ipuut range for MAX232C) is in the tatasheet that OP has read but I would had a fortune if I had a penny for each call asking for something that is in the product datasheet. Make a small edit to take back my downvote.
                      $endgroup$
                      – Dorian
                      Dec 9 '18 at 13:02
















                    4












                    $begingroup$

                    enter image description here



                    Figure 1. An oscilloscope trace of a byte transmitted by an RS232 link. Source: Wikipedia RS-232.



                    Note a few things:




                    1. Logic is inverted. A '1' is a negative voltage and a '0' is a positive voltage.

                    2. The grey area shows the valid logic level voltages. It is > 3 V for a '0' and < -3 V for a '1'.



                    I'm worried that MAX232'c Voltage level (±25) harms the LCD?





                    1. The purpose of the MAX232 is to convert from the RS232 signal levels to the 5 V logic levels of your circuit. It is, in effect, a buffer between the two. Your LCD will never see the ±25 V.

                    2. ±25 V was used to transmit over long distances at low baud rates. These days we're typically running at 9600 baud which has a limit of 15 m or so before cable capacitance becomes a problem. As a result we don't need the high voltages and if you check with a multimeter you'll find that you'll only see about ±5 to ±7 V on most devices. The reason? They're probably using the MAX232 as well.


                    You'll be fine if you follow the MAX232 recommended circuit and don't skip any of the decoupling capacitors, etc., recommended in their layouts.






                    share|improve this answer









                    $endgroup$













                    • $begingroup$
                      You missed the point here. The question was if the RS232C input can handle RS232 levels. It was not about the LCD screen itself, he was asking about the LCD module if it can be damaged.
                      $endgroup$
                      – Dorian
                      Dec 8 '18 at 11:42










                    • $begingroup$
                      Thanks, @Dorian. I understood the question and I thought I had addressed it with my paragraph including "Your LCD will never see the ±25 V." In almost 40 years working with all sorts of industrial RS232 interfaces I've never seen more than 12 V and that was in the days when devices had +/-12 V supplies. Most of my answer was giving background to the protocol and the buffering as there seemed to be some confusion there.
                      $endgroup$
                      – Transistor
                      Dec 8 '18 at 15:36










                    • $begingroup$
                      I know that what is missing in your answer ( +-30V ipuut range for MAX232C) is in the tatasheet that OP has read but I would had a fortune if I had a penny for each call asking for something that is in the product datasheet. Make a small edit to take back my downvote.
                      $endgroup$
                      – Dorian
                      Dec 9 '18 at 13:02














                    4












                    4








                    4





                    $begingroup$

                    enter image description here



                    Figure 1. An oscilloscope trace of a byte transmitted by an RS232 link. Source: Wikipedia RS-232.



                    Note a few things:




                    1. Logic is inverted. A '1' is a negative voltage and a '0' is a positive voltage.

                    2. The grey area shows the valid logic level voltages. It is > 3 V for a '0' and < -3 V for a '1'.



                    I'm worried that MAX232'c Voltage level (±25) harms the LCD?





                    1. The purpose of the MAX232 is to convert from the RS232 signal levels to the 5 V logic levels of your circuit. It is, in effect, a buffer between the two. Your LCD will never see the ±25 V.

                    2. ±25 V was used to transmit over long distances at low baud rates. These days we're typically running at 9600 baud which has a limit of 15 m or so before cable capacitance becomes a problem. As a result we don't need the high voltages and if you check with a multimeter you'll find that you'll only see about ±5 to ±7 V on most devices. The reason? They're probably using the MAX232 as well.


                    You'll be fine if you follow the MAX232 recommended circuit and don't skip any of the decoupling capacitors, etc., recommended in their layouts.






                    share|improve this answer









                    $endgroup$



                    enter image description here



                    Figure 1. An oscilloscope trace of a byte transmitted by an RS232 link. Source: Wikipedia RS-232.



                    Note a few things:




                    1. Logic is inverted. A '1' is a negative voltage and a '0' is a positive voltage.

                    2. The grey area shows the valid logic level voltages. It is > 3 V for a '0' and < -3 V for a '1'.



                    I'm worried that MAX232'c Voltage level (±25) harms the LCD?





                    1. The purpose of the MAX232 is to convert from the RS232 signal levels to the 5 V logic levels of your circuit. It is, in effect, a buffer between the two. Your LCD will never see the ±25 V.

                    2. ±25 V was used to transmit over long distances at low baud rates. These days we're typically running at 9600 baud which has a limit of 15 m or so before cable capacitance becomes a problem. As a result we don't need the high voltages and if you check with a multimeter you'll find that you'll only see about ±5 to ±7 V on most devices. The reason? They're probably using the MAX232 as well.


                    You'll be fine if you follow the MAX232 recommended circuit and don't skip any of the decoupling capacitors, etc., recommended in their layouts.







                    share|improve this answer












                    share|improve this answer



                    share|improve this answer










                    answered Dec 8 '18 at 8:32









                    TransistorTransistor

                    83.9k783179




                    83.9k783179












                    • $begingroup$
                      You missed the point here. The question was if the RS232C input can handle RS232 levels. It was not about the LCD screen itself, he was asking about the LCD module if it can be damaged.
                      $endgroup$
                      – Dorian
                      Dec 8 '18 at 11:42










                    • $begingroup$
                      Thanks, @Dorian. I understood the question and I thought I had addressed it with my paragraph including "Your LCD will never see the ±25 V." In almost 40 years working with all sorts of industrial RS232 interfaces I've never seen more than 12 V and that was in the days when devices had +/-12 V supplies. Most of my answer was giving background to the protocol and the buffering as there seemed to be some confusion there.
                      $endgroup$
                      – Transistor
                      Dec 8 '18 at 15:36










                    • $begingroup$
                      I know that what is missing in your answer ( +-30V ipuut range for MAX232C) is in the tatasheet that OP has read but I would had a fortune if I had a penny for each call asking for something that is in the product datasheet. Make a small edit to take back my downvote.
                      $endgroup$
                      – Dorian
                      Dec 9 '18 at 13:02


















                    • $begingroup$
                      You missed the point here. The question was if the RS232C input can handle RS232 levels. It was not about the LCD screen itself, he was asking about the LCD module if it can be damaged.
                      $endgroup$
                      – Dorian
                      Dec 8 '18 at 11:42










                    • $begingroup$
                      Thanks, @Dorian. I understood the question and I thought I had addressed it with my paragraph including "Your LCD will never see the ±25 V." In almost 40 years working with all sorts of industrial RS232 interfaces I've never seen more than 12 V and that was in the days when devices had +/-12 V supplies. Most of my answer was giving background to the protocol and the buffering as there seemed to be some confusion there.
                      $endgroup$
                      – Transistor
                      Dec 8 '18 at 15:36










                    • $begingroup$
                      I know that what is missing in your answer ( +-30V ipuut range for MAX232C) is in the tatasheet that OP has read but I would had a fortune if I had a penny for each call asking for something that is in the product datasheet. Make a small edit to take back my downvote.
                      $endgroup$
                      – Dorian
                      Dec 9 '18 at 13:02
















                    $begingroup$
                    You missed the point here. The question was if the RS232C input can handle RS232 levels. It was not about the LCD screen itself, he was asking about the LCD module if it can be damaged.
                    $endgroup$
                    – Dorian
                    Dec 8 '18 at 11:42




                    $begingroup$
                    You missed the point here. The question was if the RS232C input can handle RS232 levels. It was not about the LCD screen itself, he was asking about the LCD module if it can be damaged.
                    $endgroup$
                    – Dorian
                    Dec 8 '18 at 11:42












                    $begingroup$
                    Thanks, @Dorian. I understood the question and I thought I had addressed it with my paragraph including "Your LCD will never see the ±25 V." In almost 40 years working with all sorts of industrial RS232 interfaces I've never seen more than 12 V and that was in the days when devices had +/-12 V supplies. Most of my answer was giving background to the protocol and the buffering as there seemed to be some confusion there.
                    $endgroup$
                    – Transistor
                    Dec 8 '18 at 15:36




                    $begingroup$
                    Thanks, @Dorian. I understood the question and I thought I had addressed it with my paragraph including "Your LCD will never see the ±25 V." In almost 40 years working with all sorts of industrial RS232 interfaces I've never seen more than 12 V and that was in the days when devices had +/-12 V supplies. Most of my answer was giving background to the protocol and the buffering as there seemed to be some confusion there.
                    $endgroup$
                    – Transistor
                    Dec 8 '18 at 15:36












                    $begingroup$
                    I know that what is missing in your answer ( +-30V ipuut range for MAX232C) is in the tatasheet that OP has read but I would had a fortune if I had a penny for each call asking for something that is in the product datasheet. Make a small edit to take back my downvote.
                    $endgroup$
                    – Dorian
                    Dec 9 '18 at 13:02




                    $begingroup$
                    I know that what is missing in your answer ( +-30V ipuut range for MAX232C) is in the tatasheet that OP has read but I would had a fortune if I had a penny for each call asking for something that is in the product datasheet. Make a small edit to take back my downvote.
                    $endgroup$
                    – Dorian
                    Dec 9 '18 at 13:02


















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