The service is used to send alerts to communities and corporations

A Texas-based firm is suing the micro-blogging site Twitter, alleging that its three patents for a similar service are being infringed.

TechRadium's system, called Iris, provides notification technology so that alerts can be sent to many users.

Alerts can be sent to a number of devices, including mobiles.

The firm claims several organisations may choose to use the free Twitter service instead of paying for Iris, resulting in lost revenue.

Clients using the Iris system include the US army and a number of corporations and municipal organisations.

The three patents outline an "author interface" for distributing alerts and messages from a single sender to many recipients.

This "from one to many" ethos is the cornerstone of Twitter's model.

TechRadium's complaint claims that Twitter "intentionally, knowingly, and with "callous disregard", infringed on the firm's patents.

TechRadium's federal lawsuit is claiming for unspecified damages and a permanent injunction against Twitter.