⁵. Early versions of the CDPD System Specification defined a network entity called the ”Mobile Data Intermediate System”. With CDPD System Specifications preliminary release 0.8, we introduced the concept of a serving area entity and a home area entity. Unfortunately, there was concern that confusion may result from the appearance of a ”new” network component. Therefore, instead of creating yet another acronym, we opted for the notion of a ”serving MD-IS” and a ”home MD-IS”. To our dismay, this has also caused some confusion. Some readers misinterpreted the names to mean that if a M-ES is in its ”home” area, it would only interact with the ”home MD-IS”. This is not so. A perhaps better definition of function involves the mobile home function or MHF and mobile serving function or MSF; these definitions provide clarity in the case of a single MD-IS supporting both homed and visiting mobiles.