This paper proposes that the end user's perception of an "ISDN service" should reflect'three interrelated ISDN aspects, namely:\bulletISDN terminal capabilities,\bulletISDN access capabilities, and\bulletISDN network capabilities. Emphasis is placed on the ISDN terminal capabilities in supporting integrated services delivery of different levels to the end user (e.g., integrated bearer services and integrated teleservices delivery). Such a concept, integrated services delivery, is seen to suggest a useful framework for developing a wide range of possible ISDN commercial service/ product offerings. An ISDN service scenario is also described to illustrate some important communication capabilities made possible by an ISDN environment.

Bit-by-bit soft-decision decoding of binary cyclic codes is considered. A significant reduction in decoder complexity can be achieved by requiring only that the decoder correct all analog error patterns which fall within a Euclidean sphere whose radius is equal to half the minimum Euclidean distance of the code. Such a "maximum-radius" scheme is asymptotically optimum for the additive white Gaussian noise (AWGN) channel. An iterative extension of the basic algebraic analog decoding scheme is discussed, and performance curves are given for the (17,9), (21,11), and (73,45) codes on the AWGN channel.

It is shown that a majority-logic decoding algorithm proposed by Lin and Weldon for the product of anL-step and a one-step orthogonalizable code is incomplete whenLis greater than unity. An improvement is presented to overcome this disadvantage in the binary case.

In this correspondence additional results on majority-logic decoding of product codes are presented. If one of the component codes is decodable using Rudolph's nonorthogonal algorithm, and the other using Reed-Massey'sL-step orthogonalization, then the resulting product code is majority-logic decodable inLsteps, where nonorthogonal checks are used in the first step and orthogonal checks in the remaining steps. If the component codes are both decodable using Rudolph's algorithm, the product code is majority-logic decodable using the same procedure.

In this correspondence a new decoding algorithm using majority logic is proposed. This scheme, called "pseudostep orthogonalization," is basically a hybrid version of the existing majority-logic decoding methods, namely, Reed-Massey's algorithm and Rudolph's algorithm. An example is given for the (21, 5) binary cyclic code, which can correct up to four independent errors.