(Telecompaper) A total of 21 Mexican operators have joined forces to back the zero interconnection rate rule on grounds that it has resulted in lower tariffs and allowed them to invest in improving infrastructure, reports El Economista. Fixed, mobile and cable TV companies across the country have expressed their concern at America Movil's attempts to challenge the rule as part of its injunctions against the 2013-14 telecommunications reform. Article 131 of the resulting telecoms act prohibited America Movil's subsidiaries Telmex and Telcel from charging alternative operators for calls terminating in their networks due to their dominant status.