Mickey_Sadler Posted May 28, 2003 Report Share Posted May 28, 2003 Hi All,The RS-232 standard states that -3 volts to -25 volts is a logic 1, and +3 volts to +25 volts is a logic 0. The -3 volt to +3 volt region is a "transition region" and a logic state is not assigned. Most computers supply -12 volt and +12 volt output, but some laptops only use around 4 to 5 volts + and - and this is not enough to drive some equipment. I have seen the same problem with some modems connected to a laptop serial port. Sometimes they worked, sometimes not, and sometimes just marginal communications. That's probably why your programmer worked on the PC and not the laptop.Later,Mickey Quote Link to comment Share on other sites More sharing options...
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