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Recommended practice extensions for GD&T in STEP-AP210 in the context of electronic connectors



Jamie Stori, Kevin G. Brady


The purpose of this document is to extend the recommended practices for the representation of GD&T in STEP AP 210 (ISO-10303:210) in the context of packaged electronic connectors. Geometric dimensioning and tolerancing (GD&T) is critical to the design, manufacture, and assembly of electronic products. STEP AP 210 is unique in its ability to represent detailed usage views of electronic components spanning both the mechanical (MCAD) and electrical (ECAD) design domains. Within the STEP standards (ISO-10303), prior attention has been focused on the representation and presentation of GD&T in the context of three-dimensional (3D) boundary-representation (B-REP) models. In this context, GD&T annotations are typically associated with faces in the 3D model. Vendors of electro-mechanical components such as connectors typically provide detailed specifications of the mechanical properties of their components, and often will include a recommended PCB layout for the component. Both the mechanical specification and the PCB layout recommendation will often include GD&T annotations. This is particularly relevant in the context of mounting and mating features, such as mounting and alignment holes and features such as bosses, slots, and studs. Typically, the GD&T annotations are provided as a technical drawing, most often in .pdf format.
NIST Interagency/Internal Report (NISTIR) - 7716
Report Number


STEP, STEP AP210, Manufacturing, Electronics Manufacturing


Stori, J. and Brady, K. (2010), Recommended practice extensions for GD&T in STEP-AP210 in the context of electronic connectors, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed May 30, 2024)


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Created August 15, 2010, Updated October 12, 2021