Voice Procedure - Frequency Control

Frequency Control

In public radio, voice procedure controls the behavior and use of the frequency between each operator. Deregulated frequencies, such as Family Radio Service has no voice procedure, but due to the limited range of transmission it is unlikely a transmission will be heard outside of a single party. On signals open to the public with broader reception, such as citizens band, there is only enough protocol to allow operators to speak one at a time or allow emergency traffic to go through. Otherwise, there is no prioritization or rules to the communication outside of following local and federal laws regarding communication. Other stations requiring licensure such as amateur radio bands or MARS users (which includes civilian amateur radio operators) have strict usage and transmission rules which operators are trained on (as part of their licensing process) that allows authorized users to communicate. Regulated Radio frequencies often have unlicensed users who are unaware of the protocol on a certain channel and are asked to sign off if they fail to identify a callsign as a licensed operator, or are reported by licensed operators to the licensing body for possible advisement or citation. Amateur radio frequencies also may have assigned functions which may allow or disallow certain traffic including voice, such as continuous wave (see Morse code) transmission or data-only transmission frequencies.

Structured use is seen in voice procedure for government, military and disaster command usage. In law enforcement and public safety use, voice procedure follows a protocol that governs who can speak on a frequency and when. Since modern police frequencies are on a restricted bandwidth it is unlikely that an unlicensed party will interrupt communication; all operators on a frequency are assumed to be authorized to utilize a channel unless proven otherwise. Licensed radios in law enforcement often utilize trunking, or multiple frequencies selected by a control tower at random which prevents single-channel scanners from picking up a transmission. A frequency may be dispatch controlled (or controlled net) which is controlled by one control station and any parties wishing to use the frequency must direct all calls to the control station who routes calls as needed to necessary parties. A tactical frequency (or tactical net) has no control station, and is intended to be used on an ad-hoc basis for situations, such as multiple units attempting an arrest who surround a single property. Tactical frequencies may or may not be trunked and may be susceptible to single-channel scanner reception.