The fallout from the decision to remove the caps on the interconnection fees is still unclear for both the carriers and their customers.

Earlier this month, Mexico's telecommunications regulatory panel, Cofetel, ordered a 63 percent reduction in interconnection fees, to 1.25 cents a minute from 3.36 cents.

TT Net, of course, knew from the start that interconnection fees were high.

But Mr. Koide and the government are ignoring the experience of the United States and other countries where interconnection fees have been reduced.

"What we consider unfair is that if N.T.T. can afford to lower rates that fast in that business, why can't they reduce interconnection fees?"

Some of the new providers of telephone service over the Internet say they should not be subject to the same interconnection fees as the traditional phone services.

The regulators are further hampered by their own efforts to make a case to politicians for supporting sharply reduced interconnection fees.

It is not yet known, for example, what interconnection fees the two existing telephone companies will collect for carrying competitors' traffic.

And until recently, they complained that Telmex charged excessive interconnection fees.

Revenues from voice services include traffic charges, interconnection fees, and roaming charges.