One of the dial-up numbers is run by a small ISP called the French Data Network, which said it was the first time it had set up such a service. Its modem has been providing a connection "every few minutes," said Benjamin Bayart, FDN's president, speaking in an online chat.

The international dial-up numbers only work for people with access to a telephone modem and an international calling service, however. So although mobile networks have been suspended in some areas, people have about how others can use their mobile phones as dial-up modems.

The few Egyptians able to access the Internet through Noor, the one functioning ISP, are taking steps to ensure their online activities are not being logged. Shortly before Internet access was cut off, the Tor Project said it saw a big spike in Egyptian visitors looking to download its Web browsing software, which is designed to let people surf the Web anonymously.

"We thought we were under denial-of-service attack," said Andrew Lewman, the project's executive director. The site was getting up to 3,000 requests per second, the vast majority of them from Egypt, he said. "Since then we've seen a quadrupling of Tor clients connecting from Noor over the past 24 hours," he said.

Even with no Internet, people have found ways to get messages out on Twitter. On Friday someone had set up a account where they posted messages that they had received via telephone calls from Egypt. A message reads: "Live Phonecall: streets mostly quiet in Dokki, no police in sight. Lots of police trucks seen at Sheraton."