AT&T’s deployment of fiber internet in California has come primarily in high-income neighborhoods while the company infrastructure in other areas has lagged behind state and federal broadband standards, a report found.

Researchers from the Haas Institute for a Fair and Inclusive Society at the University of California, Berkeley published its report “AT&T's Digital Divide in California” Tuesday, which found California households with access to AT&T's fiber service have a significantly higher median income than those without access.

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According to the report, households with access to fiber internet from AT&T have a median income of $94,208. By contrast, California neighborhoods with access only to AT&T’s DSL offering have a median income of $53,186.

The divide in service provided is stark. While AT&T’s fiber service is capable of providing download speeds up to 1Gbps, the company’s DSL connection offers 768kbps to 6Mbps — speeds that do not meet the federal broadband standard of 25Mbps down and 3Mbps up.

U-verse VDSL, which provides download speeds from 12Mbps to 75Mbps, is available in areas where the median income is $67,021.

Just over 4 million households in California served by AT&T, or 42.8 percent of the company’s service area in the state, do not have access to an internet connection that meets the federal definition of broadband.

Nearly 20 percent of all customers in the state don’t have access to broadband internet as defined by California’s lower standard of 6Mbps download and 1.5Mbps upload speeds.

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"Because there is no regulatory oversight of AT&T’s fiber-to-the-home deployment, AT&T is free to choose the communities in which it builds its all-fiber GigaPower network," the report concluded.

"Our analysis finds that AT&T has built its all-fiber network disproportionately in higher income communities. If this pattern continues, it has troubling consequences for low- and moderate-income Californians, leaving many without access to AT&T’s gold standard all-fiber network and exacerbating the digital divide."