The viability of urban cable television (CATV) as an economic phenomenon is examined via a case study of its feasibility in Boston, a microcosm of general urban environment. To clarify cable's economics, a unitary concept of viability is used in which all local characteristics, cost assumptions, and growth estimates are structured dynamically as a simulated cable system and compressed to a single index--a threshold subscriber monthly cost (SMC). The report's first section investigates the inverse relation of system cost to population density, describes a general method for representing fixed costs as an incremental addition to a base SMC, and presents two simulations of cable's viability in Boston. Next, Boston's local characteristics and potential system size are studied at three levels of resolution--districts, communities, and census tracts, after which a general index of viability is derived for conditions not necessarily local to Boston. The final section provides the documentation for the data definitions and cost assumptions used in the report and presents a general guide to CATV cost estimating. (Author/PB)