In this activity:

• The implementers write source code, adapt existing source code, compile, link and perform unit tests, as they implement the elements in the design model. If defects in the design are discovered, the implementer submits rework feedback on the design.
• The implementers also fix code defects and perform unit tests to verify the changes. Finally, the code is reviewed to evaluate quality and compliance with the Programming Guidelines.

The tasks carried out by the implementer tend to be done by a single person. The review task is best carried out by a small team staffed by cross-functional team members, typically more senior members of technical staff with greater experience into common problems and pitfalls encountered in the programming language. Special expertise may be required in the problem domain, as is often the case in systems involving telephony or devices with special interfaces. Expertise in specific algorithms or programming techniques may also be required.