Testing the RS232 loopback plug

Test the plug by attaching it to the serial port of the Techline computer or into a certified Tech2 USB-2-serial adapter. Download a serial terminal application like RealTerm to diagnose the loop-back functionality.

Now plug your RJ-45 loop-back adapter into the Tech2 device and navigate to the RS-232 test. Depending on the software version there are various options to get to the RS-232 test menu.

While using the (SAAB 44.000 .bin file)[/content/which_.bin-files_are_available/SAAB.html] you need to follow this procedure;

  • Insert the loop-back plug into the RJ-45 port
  • Press PWR to turn on the Tech2
  • Title screen, press ENTER
  • F2: Tools Options
  • F3: Field Services Diagnostics
  • F3: Selectable Main PCB
  • F2: RS-232 LoopBack

While using the (SAAB 148.000 .bin file)[/content/which_.bin-files_are_available/SAAB.html] you need to follow this procedure;

  • Insert the loop-back plug into the RJ-45 port
  • Press PWR to turn on the Tech2
  • Title screen, press ENTER
  • F2: Tool Options
  • F0: Tech2 Self Test
  • Press EXIT on the notification screen
  • F3: Selectable Main PCB
  • F2: RS-232 LoopBack

Now the Tech2 should respond with the following: RS-232 Test: Passed

If the Tech2 responds with RS-232 Test: LoopBack Not Connected or ADDRESS ERROR - PROCESSOR HALT the chances are high that the MAX202 or the MAX232 is borked, which means replacing the SMD mountec RS-232 communications chip (SOIC type), noted as U202 on the main PCB.