ISO 18438:2013是一系列文件中的一个，这些文件规定了车载子网将提供符合SOIS标准的服务。 ISO 18438:2013定义了SOIS子网测试服务提供的服务和服务接口。其范围是仅指定服务，而不是指定通过各种车载数据链路提供服务的方法。 ISO 18438:2013符合《航天器机载接口服务绿皮书》中规定的原则，并打算与之一起应用。提供该服务的协议将针对各个链路进行记录，这可能属于各个任务、机构或CCSD的权限，具体取决于未来的情况。

ISO 18438:2013 is one of a family of documents specifying the SOIS-compliant services to be provided by onboard subnetworks. ISO 18438:2013 defines services and service interfaces provided by the SOIS Subnetwork Test Service. Its scope is to specify the service only and not to specify methods of providing the service over a variety of onboard data links. ISO 18438:2013 conforms to the principles set out in the Spacecraft Onboard Interface Services Green Book and is intended to be applied together with it. The protocols which provide this service are to be documented for individual links, and this may be in the purview of individual missions, agencies, or CCSDS, depending on future circumstance.