(CNN) Arguments in a technical case at the Supreme Court really resonated Tuesday when Justice Stephen Breyer's cell phone went off.
Mobile devices are prohibited in the court during oral arguments. A spokeswoman for the court chalked up Breyer's phone faux-paus as an oversight.
"He doesn't usually bring his phone and he forgot," said Kathy Arberg.
The Washington Post's Robert Barnes was in court and tweeted that Breyer appeared "red-faced" as the justice struggled to silence the offending device.
The pinging sound -- the justice apparently has decided against a more distinctive ringtone -- occurred near the beginning of Bristol-Myers Squibb v. Superior Court of California. It's a technical personal jurisdiction case that presents this question:
"Whether a plaintiff's claims arise out of or relate to a defendant's forum activities when there is no causal link between the defendant's forum contacts and the plaintiff's claims -- that is, where the plaintiff's claims would be exactly the same even if the defendant had no forum contacts."