61200051L1-1D ISU 2x64 Dual Port ISDN Service Unit User Manual 9Chapter 2ISDN ServiceISDN ORDERING CODESISDN is a complex service with many network options. Obtain-ing service from the local telephone company and long distanceproviders can be complicated.In North America, the development of ISDN ordering codes(IOCs) simplifies the process of ordering ISDN service. The ISDNSolutions Group, a consortium of ISDN equipment vendors, ser-vice providers, and Bellcore, established these codes to representpredetermined line configurations for ISDN Basic Rate service forspecific applications.ADTRAN and Bellcore have registered and tested eight genericIOCs. These IOCs are supported by all major local exchange car-riers as well as several independent carriers. After reviewing thefollowing list, order ISDN lines from the local service provider.Request the appropriate IOC for your application. If the local ser-vice provider does not support IOCs, see Ordering ISDN WithoutIOCs on page 125.Capability S (previously Generic Data M) ordering code is rec-ommended for 2x64 applications. It is the most feature-rich andsupports most voice and data applications. The voice capabilityis not necessary for ISU operation in 2x64 in data-only applica-tion, however it is useful in troubleshooting a mis-configuredISDN line. In some areas, ISDN tariffs may warrant the use ofordering codes with less features. For example, in a particularregion, there may be additional monthly expense associated withhaving voice service on each B channel. If you have a data-only
