The Mexican Supreme Court ruled that telephone companies who are unable to reach an agreement on interconnection fees must accept the rates established by the Federal Telecommunications Commission, or Cofetel.

The justices, who took up the case after two lower courts had handed down opposing decisions, found no justification for allowing the telecommunications regulator's rates to be challenged in court and suspended until a dispute between two companies is resolved.

In their 6-4 ruling on Tuesday, the judges found that to protect the interests of consumers it is not enough for companies' networks to be interconnected.

Authorities also must guarantee "efficient conditions in an atmosphere of healthy competition among operators and (ensure) that consumers' interests are protected insofar as guaranteeing better prices, variety and service quality."

The justices' debate centered on whether allowing federal judges to suspend rates handed down by Cofetel affected the public order and harmed the interests of consumers.

Since the end of the 1990s, several emerging market players have requested that Telmex - owned by multi-billionaire Carlos Slim and the country's only fixed-line operator for decades - allow them to connect to its vast network.

Telmex - and later Slim's Telcel, a unit of regional giant America Movil and Mexico's dominant wireless operator - often set interconnection fees that rival operators considered to be too high. Cofetel would often intervene in the dispute and set the rates, but Telmex and Telcel had the option of challenging them in court.

In recent months, Cofetel has resolved several rate disputes involving Telcel by setting an interconnection fee of 0.39 pesos ($0.03) per minute, far below the rate that market leader had been seeking.