Editing ISDN (section)

=== Rollout ===

With digital-quality voice made possible by ISDN, offering two separate lines and continuous data connectivity, there was an initial global expectation of high customer demand for such systems in both the home and office environments. This expectation was met with varying degrees of success across different regions.

In the United States, many changes in the market led to the introduction of ISDN being tepid. During the lengthy standardization process, new concepts rendered the system largely superfluous. In the office, multi-line digital switches like the [[Meridian Norstar]] took over telephone lines while [[local area network]]s like [[Ethernet]] provided performance around {{nowrap|10 Mbit/s}} which had become the baseline for inter-computer connections in offices. ISDN offered no real advantages in the voice role and was far from competitive in data. Additionally, modems had continued improving, introducing {{nowrap|9600 bit/s}} systems in the late 1980s and {{nowrap|14.4 kbit/s}} in 1991, which significantly eroded ISDN's value proposition for the home customer.{{sfn|Cioffi|2011|p=32}}

Conversely, in Europe, ISDN found fertile ground for deployment, driven by regulatory support, infrastructural needs, and the absence of comparable high-speed communication technologies at the time. The technology was widely embraced for its ability to digitalize the "last mile" of telecommunications, significantly enhancing the quality and efficiency of voice, data, and video transmission over traditional analog systems.

Meanwhile, Lechleider had proposed using ISDN's echo cancellation and 2B1Q encoding on existing T1 connections so that the distance between repeaters could be doubled to about {{convert|2|miles}}. Another [[standards war]] broke out, but in 1991 Lechleider's {{nowrap|1.6 Mbit/s}} "High-Speed Digital Subscriber Line" eventually won this process as well, after Starr drove it through the ANSI T1E1.4 group. A similar standard emerged in Europe to replace their E1 lines, increasing the sampling range from 80 to 100&nbsp;kHz to achieve {{nowrap|2.048 Mbit/s}}.{{sfn|Cioffi|2011|p=34}} By the mid-1990s, these [[Primary Rate Interface]] (PRI) lines had largely replaced T1 and E1 between telephone company offices.