We were trying to test a pair of radios with a data loop-back and were again making the same old mistakes and then wondering what the heck is going on. It is just amazing how many times I have sat down and scratched my head with these things - it feels like I never learn or remember! The mistake we make over and over again is to expect the wrong read/write behaviour from a serial port utility: A serial port is a bidirectional device. A program will grab the device file handle and open the device file either as 'Read', 'Write' or 'Read/Write'. Simple programs like ' cat ', ' echo ', ' bash ' (read, write), ' head ', ' tail ' and ' of ', all open the device file as either ' Read ' or ' Write ', never ' Read/Write '. Complex programs like ' cutecom ', ' minicom ', ' screen ' and ' netcat ', open the device file as ' Read/Write '. So, one ca
Autonomous planes, trains and cranes...