PENNSYLVANIA, United States – AT&T Inc said yesterday it would invest US$1 billion to upgrade its business network, services and products for large companies worldwide as well as for small US firms as network traffic in global economies migrate from voice to video and data.

The investment brings to more than US$4 billion the total that AT&T has spent to upgrade its systems and services for over 3.5 million businesses since 2006.

The changes range from increasing US broadband speeds to 24 times the slowest DSL speeds available over phone company copper wires to laying additional undersea cables to boost data flow capacity to Europe, Asia and elsewhere.

AT&T has previously announced plans to boost its mobile broadband capabilities, such as investing more in Wi-Fi and the next generation broadband technology called Long Term Evolution, so executives on the go can have smoother, easier online access. It will increase support for wireless devices, such as netbooks and electronic readers, for businesses.

AT&T has also indicated plans to delve more deeply into so-called cloud computing services as well, an increasingly popular option in which it would manage software applications and store data for corporate clients off-site.

The phone company, which is based in Dallas, said it plans to open another Internet data center in London and finish expanding centers in Ashburn, Virginia, and Piscataway, New Jersey.

Its shares slipped 15 cents to US$26.16 in morning trading.