ATMnet was a regional Internet service provider (ISP) formed in 1994 and operated until its purchase by Verio in November 1997 as part of their national roll-up of regional ISPs.

ATMnet was originally an operating unit of Visicom Laboratories Incorporated (Visicom) called Visicom Network Services (VNS). VNS was started by two Visicom employees (Mike Trest and Tom Lettington) as an experimental entry into the rapidly expanding ISP marketplace shortly after the government allowed commercial use of the Internet infrastructure. VNS initially provided dial-up services in the San Diego market and later provided dedicated Internet services to businesses through T1 and fractional T1 "local loop" circuits. As VNS was launched from Visicom as and independent entity, the founders were joined by Jim Browning, a co-founder of Visicom, and ATMNet was formed. ATMnet operated under the domain names and 

Source: Wikipedia