The phones began ringing early yesterday at Linda Schade's Takoma Park home, jangling regularly through the morning and afternoon as frustrated voters called to complain about long lines, short tempers and -- most important for Schade -- problems with the state's electronic voting machines.

The Schade home -- which doubles as headquarters of TrueVoteMD, a group that has been highly critical of the new machines -- was crowded with volunteers, some chatting with one another, some fielding calls and some who appeared simply to be soaking up the bustling, urgent vibe.

The group has battled state election officials in court over what it contends is flawed technology in the touch-screen voting machines. They predicted a deluge of problems, but election officials said there were no widespread difficulties.

By the time polls closed, Schade said, TrueVoteMD had received about 500 calls that were a mix of complaints about crowded polling places and problems with the touch-screen machines.

In some cases, the group was having technological problems of its own. The four phone lines set up in Schade's house jammed repeatedly, sometimes rolling callers into a telephonic netherworld instead of voice mail, Schade said.

Schade and other TrueVoteMD members said they are convinced the electronic voting machines are problematic.

"In some polling places, there's a sense of pandemonium," Schade said. "There's widespread problems."

That didn't appear to be the case in at least one polling site, Flower Hill Elementary School in Gaithersburg.

There, TrueVoteMD poll watcher Kathie Evans said she fielded one technology-related complaint, from a man who said it seemed as if there were fewer voting machines yesterday than in Maryland's primary elections in the spring.

Mary Wagner, spokeswoman for the state elections board, said yesterday that the state had not received many complaints about the machines. "Everything that I've heard has certainly been mostly human error," she said.

Elections officials had said earlier that they had confidence in the machines and expected no major problems.

Schade and Bob Ferraro, a fellow activist, formed TrueVoteMD shortly after a Johns Hopkins University computer scientist issued in July 2003 a report that was critical of the machines.

It was the first of several studies finding fault with the Diebold Election Systems computers, which were purchased by the state for $55 million.

Critics said the touch-screen voting system is unreliable and easily tampered with. In September, Maryland's highest court refused to order security upgrades to the system or to require paper ballots for voters who did not want to use the computers.

A coalition of those opposing the machines had asked the courts to order machines set aside for the election and to require the state to have a paper audit trail, but the group scaled back, asking in the end for the optional paper ballots and repairs to the security of the machines.

TrueVoteMD plans to compile a report and analysis of the complaints it received yesterday. About 600 volunteers fanned out in 13 counties to take voter complaints and watch for technological problems. They carried with them fliers to be filled out by voters who had problems with the machines.

On those fliers was a phone number that reached Schade's home. On the other end of the line were call takers such as Julie Weber.

Weber sat at a computer terminal in a second-floor study of Schade's house. She started taking calls before polls opened at 7 a.m. and planned to work until about 10 p.m. By about 1 p.m., she had taken approximately 50 calls, she said.

A poll watcher in Frederick called to say that a machine had crashed and that election judges allowed a person on that machine to vote again on another machine.

"That could easily be a double vote," Weber said after the call. "And we'd never know. There's no paper trail."