Below is an example of setting up Accounting using the acc module.

  #---------------------------------------------------------------------------
  # M4 defines
  #---------------------------------------------------------------------------
  define(`OPENSER_USER',          `user')
  define(`OPENSER_PW',            `password')
  define(`OPENSER_DATABASE',      `openser')
  define(`OPENSER_DATABASE_HOST', `localhost')
  define(`FLAG_ACC',           6)
  define(`FLAG_ACC_DB',        7)
  define(`FLAG_MISSED_CALL',   8)

  #---------------------------------------------------------------------------
  # load modules
  #---------------------------------------------------------------------------
  mpath="/usr/local/lib/openser/modules"
  loadmodule "acc.so"

  #---------------------------------------------------------------------------
  # acc params
  #---------------------------------------------------------------------------
  modparam("acc", "db_url", "mysql://OPENSER_USER:OPENSER_PW@OPENSER_DATABASE_HOST/OPENSER_DATABASE")
  modparam("acc", "db_flag", FLAG_ACC_DB)
  modparam("acc", "db_missed_flag", FLAG_MISSED_CALL)
  modparam("acc", "log_level", 3)
  modparam("acc", "log_flag", FLAG_ACC)
  modparam("acc", "log_missed_flag", FLAG_MISSED_CALL)
  modparam("acc", "log_fmt", "cdfimorstup")
  #modparam("acc", "multi_leg_enabled", YES)
  #modparam("acc", "src_leg_avp_id", 110)
  #modparam("acc", "dst_leg_avp_id", 111)
  modparam("acc", "report_ack", YES)
  modparam("acc", "report_cancels", YES)
  modparam("acc", "failed_transaction_flag", YES)
  modparam("acc", "early_media", YES)

  route {
  ...
  #---------------------------------------------------------------------------
  # Setup Accounting
  #---------------------------------------------------------------------------
  if (is_method("BYE|CANCEL")) {
    setflag(FLAG_ACC);
    setflag(FLAG_ACC_DB);
  } else if (is_method("INVITE")) {
    setflag(FLAG_ACC);
    setflag(FLAG_ACC_DB);
    setflag(FLAG_MISSED_CALL);
  };
  ...
  }