From Zendegi by Greg Egan:

When they came within sight of the picket line, Martin saw that the usual Referendum! signs had been supplemented with photographs of Ansari and a new slogan that Behrouz translated as ‘Murderers, get lost!’ That soldiers weren’t tearing the signs from people’s hands was no less amazing than if they’d borne the strongest profanities, given that this accusation and advice was meant for the government. Martin took out his new phone and snapped some pictures of the pickets, trying to balance a fervent wish to avoid being seen by the soldiers with a fear that if he looked too furtive the people around him would take him for an informer. One young man did move towards him, scowling, but Behrouz stepped in and whispered an explanation that seemed to satisfy him. He checked the pictures and queued them up for their long, tortuous journey to Sydney.

Even back in his office in Tehran he was no longer able to use the internet; he had to print out his copy and fax it. He’d tried uploading files direct to the newspaper’s computer using a dial-up modem, but the government was degrading international phone lines to the point where the modems just kept hanging up; even the faxes he sent arrived peppered with static and were only legible if he used an absurdly large font. The conventional mobile service was now disabled across the country, and every major city had installed transmitters to jam the frequencies that had enabled the mesh network Mahnoosh had showed him at the demonstration in Tehran. Slightly Smart Systems, though, had left one last option open: infrared.

Their phones could pass data to each other by IR along a line-of-sight path, and whilst the government could interfere with the system in a limited space, such as a stadium or public square, in principle, they could no more jam it everywhere than they could flood the whole country with strobing blue disco lights. The point-to-point bursts of IR carried email and news in much the same way as those services had worked in the days before the internet proper, when university computers had been linked up only sporadically via brief late-night phone calls but, in lieu of fixed landlines, the modern incarnation involved ‘polling’ phones in the vicinity to discover which ones were in a position to exchange data.

Before the restrictions on intercity travel had come in, Slightly Smart email had diffused across the country and over the borders in a matter of days; from Tehran, Martin had sent a test message to his editor and received a reply in four days, probably via Turkey. No doubt there would soon be government programmers working on ways to clog the whole system with spam – and plainclothes police strolling around arresting anyone who responded to their polling signal – but for now the benefits were worth the risk, and a crowd of Ansari supporters was a good place to start. Martin switched his phone to polling mode and parked it in his shirt pocket with the tiny lens of the IR transceiver exposed, leaving it to try its secret handshake on as many passing strangers as it liked.