This paper describes prototyping work for service hybrids, flexible circuits that form an integral part of the silicon strip modules to be used in the CMS Phase-2 Outer Tracker. The service hybrid is responsible for power distribution, data serialization, and opto-electrical conversion. First prototype service hybrids, featuring the complete functionality, have been developed, produced, and characterized. In addition a first prototype of a test board, which allows to test all aspects of the complex service hybrids, as will be required during the production phase, has been developed. After a short introduction to the CMS strip modules the functionality of the service hybrid will be explained and the present prototype will be described, followed by selected test results. The test system concept will be introduced and first results will be presented.