Another legal setback for Apple as the tech giant was ordered Wednesday by a U.S. federal court in Texas to shell out more than $US368 million for patent infringement, stemming from the technology behind FaceTime, the video call feature that is a mainstay on Mac computers, iPhone and iPad.

A Texas jury sided with security software firm VirnetX's arguments that the secured network connection governing the popular Apple offering was originally the handiworks of the Nevada-based firm's founder, who designed the communication tool for initial use of the U.S. Central Intelligence Agency (CIA), Bloomberg reported on Thursday.

The favourable ruling came following a similar victory for VirnetX, which in 2010 forced a $US200 million settlement from software giant Microsoft, with the same technology as the point of contention. Next target for the little-known firm is Cisco, which it is set to meet in court hearings in early 2013.

Judging from the pattern of legal victories it has successfully scored against high-profile adversaries so far, it wouldn't be remotely surprising for VirnetX to include Cisco on its list of giant slays.

"We are extremely pleased with the outcome of our suit with Apple," VirnetX Chief Executive Kendall Larsen said in a statement.

"This victory further establishes the importance of our patent portfolio," Agence France Presse (AFP) reported Mr Larsen as saying.

Apple has yet to issue comments on the matter but is expected to appeal the verdict, news reports said.

Lately, Apple's legal wars against its competitors have been trudging along rough roads, particularly its campaign to decimate bitter rival Samsung, whose smartphone and tablet lines have emerged as the biggest threats to the tech titan's money-makers.

As courts in the United States and elsewhere started reversing Apple's earlier triumphs, most notable of which was a U.S. jury decision that ordered Samsung to pay damages of $US1.04 billion to Apple, competitors are fast catching up with its hot-selling gadgets.

The latest tech market data issued by IDC showed that Samsung has maintained its lead in the smartphone arena as of September 2012, with Android phones, which is the backbone of Samsung handsets, capturing around 75 per cent of the market in the same period.

In the tablet rivalry, Apple has maintained its lead in Q3 2012 by shipping out more than 50 per cent of the total units that hit global markets from July through September but IDC researchers also noted that Apple's share of the market it virtually invented is constantly retreating.

Competitors like Samsung, Amazon and even Google appeared to have cracked the code in making the tablet war more exciting, with Samsung successfully issuing both affordable and premium tablets that consumers seem to start embracing, while Amazon and Google gained considerable inroads via their dirt-cheap slates with powerful hardwares and features.

Samsung could soon breathe hard on Apple's neck, IDC said, with its tablet shipments doubling in the third quarter this year, while Amazon and Google were both picking up pace that could push them shortly within the striking distance of Apple.