Mitel SX50

...

1. Within the PBX programming interface choose Systems Options Programming.
2. Access

   Referencemacro
   Label Command 100

   ,

   Referencemacro
   Label register 14

    .

3. Ensure the

   Keywordmacro
   Label Enabled for both incoming and outgoing trunk calls

    option is enabled. 

4. Make sure that SMDR is enabled in all of your Class of Services (Command 121-129) and trunk groups (Command 151-156).

...