From: C@in.the.hat   
      
   Measure frequency? For what?   
      
   ----------------   
      
   "Martin Riddle"  wrote in message news:j5l8b2$knh$1@dont-email.me...   
   Never put UPS's in series. Two or more powering separate devices is ok.   
   UPS's measure incoming freq and voltage of a AC line, usually   
   calculating the RMS of the line voltage.   
   Most UPS's are quasi sine output, so that screws up the calculations.   
      
   Cheers   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)