The 24-hour walkout by the Taxi Workers Alliance will begin at 5 a.m. on Oct. 22, and will include a lunchtime demonstration outside the Taxi & Limousine Commission in Lower Manhattan, said its executive director, Bhairavi Desai.

Desai predicted thousands of drivers would participate. The group says it represents about one-fifth of the city's 44,000 licensed taxi drivers.

Mayor Michael Bloomberg has said that the city would be ready, but told the cabbies it was in their best financial interest to keep working.

The strike would be the second in two months.

The Alliance pronounced last month's two-day strike a resounding success, but city officials said its impact was minimal. The two sides disputed the extent of taxi drivers' participation, but at least hundreds and probably thousands of drivers idled their taxis.

The dispute centers on a requirement that all taxis have the GPS and credit-card systems installed by Jan. 31, 2008.

City officials say the devices are plums for passengers, making payments more convenient and lost items easier to locate.

But Desai said that the 5 percent surcharge on each credit card transaction "is simply a wage cut," while the GPS "we find really objectionable (because) it's a tool of labor control."

A federal judge has declined to block the technology requirement and told the drivers and city to try to negotiate a settlement before an Oct. 10 court date.