Research objectives and hypothesis/research questions:
The aim of the study was to answer the question: do the data transfer parameters using mobile networks and fiber optics support the hypothesis of substitutability between the two media? If both techniques produced comparable results, the development of fiber optic networks would be unjustified, as the network providing mobile internet access covers 98% of Poland’s territory.

Research methods:
Comparison – in 2024, 5,400,000 tests of fixed-line internet parameters and 615,000 tests of mobile internet delivered over 5G technology were conducted, initiated by speedtest.pl users. Each test is unique, as it examines network parameters at the time of testing. Each has unique parameters: download time, upload time, and ping.

Main results:
The number of fiber-optic network users increased by approximately 27% between 2019 and 2023, demonstrating the demand for stable, fixed-line internet delivered via fiber. During this same period, we observed an average 11% decline in the number of copper network (xDSL) users, while the number of Docsis users (a medium used for cable TV) remained stable. Both technologies will remain complementary in the long term, because while mobile data transfer speeds result from their technical parameters and do not exceed 300 Mb/s, FTTx networks are limited to 8 Gb/s, and the most popular packages, such as 300 Mb/s, are offered for marketing purposes. There is no justification for offering faster transfer rates to mass consumers.

Implications for theory and practice:
The most important are the practical implications described in the article: optical fibers offer much more stable data transmission, especially for business users, in areas with lower population density, where it is possible to receive data provided by mobile operators, the FWA (fixed wireless access) technique may be an alternative to optical fibers.