Acer Inc. and ASUS Computer International on Tuesday took different tacks in responding to allegations that their smartphones and tablets had infringed on patents that underpin Siri.

The computer hardware companies earlier this year joined the ranks of 11 other tech firms to be sued in Delaware federal court by IPA Technologies Inc. over patents related to the popular electronic assistant featured on Apple Inc. devices.

For Acer and ASUS, this is the second time they found themselves sparring with IPA over the so-called '021 and '061 patents, which IPA acquired from SRI International Inc. in May 2016. The earlier cases—along with four others targeting tech giants Dell, HP Inc. and Toshiba America Inc.—were settled within weeks of their filing in October 2016.