The easiest way for criminals to get arrested is to be overheard on the phone by police.

To avoid this weak link in its organizational chain, the Zeta drug cartel has installed hundreds of antennas and repeaters all over Mexico.

Michael Weissenstein of the Associated Press reports the network consists of everything from radio towers, to handheld two-way radios that transmit over the tower's waves.

This allows the cartels to speak over an encrypted line, out of sight of the Mexican government, and to reach far deeper into the interior of the country than would be allowed with cell phones.

In their efforts to knock out the cartels' lines of communications, Weissenstein says the Mexican government has seized at least 167 antennas, 155 repeaters, 166 power sources, 71 pieces of equipment, and 1,446 handheld radios. The network extends from the eastern gulf coats into Guatemala.

The sophisticated setup was put in place by the former Mexican special forces soldiers who comprise the heart of the Zeta cartel by using communications specialists to install, run, and update the network.

While other cartels are using the same design, the Zeta's radio network is by far the largest.