A multitude of options are available here, too. Recently, 2.4GHz unlicensed spread-spectrum devices have become popular. Stations that employ return links that piggyback on the broadcast signal are at a considerable disadvantage when the station goes off the air. Dial-up control systems are popular, especially since they allow the use of floating control points and give the chief engineer direct access to the transmitter from any phone. Telephones access and control have become common in many systems.
Some systems utililize different access and control methods than their traditional counterparts.
The use of dial-up control has been subject to controversy for many years. However, the rules require that the phone line at the transmitter site be dedicated to that purpose. If the station engineer has dialed in to check meter readings, the station's control point operator cannot access the remote control because the phone is busy. Therefore, if the phone line is not dedicated, an alternate method of transmitter shutdown must be devised. It seems that when the FCC relaxes the Rules on an issue, some want to push things even further.