Intelligent communications-line power applications for ISDN

The paper demonstrates that it is possible to design a full featured line powered ISDN phone within the power budget specified by the CCITT/ANSI. This is made possible with a combination of circuit component selection, hardware and software design techniques. It also demonstrates that migration to low voltage designs will allow the designer to add extra features such as data capability within the same power budget. An interim solution until all the components are available in 3 V versions is the use of mixed voltage design. The motivation towards line power devices is convenience to the user and will lend better user acceptance to ISDN terminal equipment-phones, data sets, etc. Which is critical to the success of ISDN deployment.