Unit-to-unit -- Handhelds have a range of about one mile depending on the terrain. Mobile and base station ranges increase to between five and 10 miles depending on terrain. In order to increase these unit-to-unit ranges, users incorporate the use of a local repeater into their system.
Repeater -- Repeaters are strategically located in every community to give the greatest coverage possible. Repeaters receive a radio signal and immediately retransmits that signal. Since the repeater has a much higher output power and is usually located at a higher elevation, the repeater is an excellent way to extend the coverage range of a mobile or handheld.
Radios on repeater systems usually have an additional channel that enables them to talk unit-to-unit at short ranges, such as within a warehouse or on a job site without using the repeater.
DTMF -- Dual Tone Multi Frequency is a tone coding system used by phone company. Most two-way radios can be enhanced by a telephone interconnect option. This allows users of mobiles or handhelds to make or receive standard telephone calls over the two-way radio. Phone conversations on radios are conducted in a half-duplex mode, that is, only one party can talk at a time.
Tone -- Also known as coded squelch allows listeners to hear only those messages intended for them. The two most common types of coded squelch are analog tone coded squelch (CTCSS or Private Line - PL) and digital coded squelch (DCS or Digital Private Line - DPL). Squelch refers to circuitry in a radio used to reduce, or eliminate unwanted signals and noise before they are heard in the speaker.
Talkaround -- Frequency in a radio which allows users to avoid using the repeater especially when they are at the same location within one mile of each other. The frequency allows you to "talk around" the repeater, which is the same as operating on a simplex frequency.
Action Communications, Inc.