# Using the Diagnostic Commands - Testbox window
| Expert information
The Diagnostic Command - Testbox window allows you to send diagnostic commands directly to a connected transmission control unit. Communication including the security access is established as set in the ALADIN Setup, i.e. for testing services that are provided only in a specific diagnostic mode, this mode must have been set in the timing parameters in the ALADIN Setup.
| The Testbox diagnostic command is available as of the 'Expert' user level (access authorization).
| How to open the Testbox diagnostic command:
Click the EOL / Adjust and then the Commands - test box button in the main window.
| How to use the Testbox diagnostic command:
> As specified in the KWP standard ISO 14230, the diagnostic command is entered in hexadecimals in the "Request" line, starting with the service identifier (SID). If you want to read the event memory, for example, the entry is: 18 02 FF FF, if you want to read the LocalIdentifier 04, the request command is 21 04. The command can be executed either once or cyclically. The transmission control unit response is displayed in the response field. Communication can also be monitored in the Message window. Several diagnostic commands can be entered and executed subsequently. Separate individual diagnostic commands using the vertical hyphen "|". If the local identifiers 04, 0B and 02 are to be read subsequently, enter the command sequence: 21 04 | 21 0B | 21 02 in the request field. If you select the option Send cyclically , only the last command will be repeated cyclically. This allows for creating a command sequence with subsequent cyclical reading of the event.
> | Starts communication with a Voith transmission control unit and sends the diagnostic commands indicated in the request line either once or cyclically.
> | Ends a request that is sent cyclically to the transmission control unit.
| Further expert topics:
More information on: Requests More information on: Service identifiers More information on: Negative Response Codes (NRCs) More information on: KWP addresses, DiagnosticMode and BaudrateIdentifier
| Further topics:
More information on: ALADIN Setup More information on: Message window More information on: KWP protocol Up > Higher-level section © by Voith Turbo GmbH & Co. KG send remarks to joachim.ehleiter@voith.com (electronic department) or r.theilacker@voith.com (electronic department)