An overview of further accessories (e.g. connectors and cables) can be found under the following link:
http://www.siemens.com/distributeddrives-supplementaryproducts

For further information about the connecting cables and plug-in connectors mentioned above, please refer to Catalog IK PI.

Further selected accessories are available from Siemens Solution Partners.
Select "Distributed Field Installation System" as technology in the "Solution Partner Finder".
http://www.siemens.com/automation/partnerfinder