Everybody shares a single frequency. It's a typical "walkie-talkie" style of speaking: only one person can talk at a time. An unlimited number of users may be in a network including headsets, body radios, and compact bases (listen-only or simplex with microphone). There is no physical limit to the number of people in a simplex network. Two or more networks can coexist side by side if they use different frequencies without hearing or talking to each other.

Simplex network made up of equal headsets

This network configuration shares two frequencies. A private transmit frequency is generally assigned to a supervisor or team leader who can speak whenever they want to using a repeating headset, body radio, or base station. The balance of the team transmits on a shared frequency (using VOX or a push to talk PTT switch) to the Repeating radio. (Note: team members other than single supervisor can only speak one at a time)  The team hears each other by receiving the signal transmitted from others in the team after it is "repeated" from the supervisor's Repeating radio. This type of network is ideal when one person MUST be able to communicate at all times OR if you want to pipe in pages from an intercom. The network will not work, however, unless you have a working Repeating radio turned on and operating.

Half Duplex Network utilizing a repeating headset as controller

Half Duplex Network utilizing a repeating base as controller

This radio is used/worn only by the supervisor or team leader in a network of half-duplex radios. See the description above.

The full duplex configuration resembles a telephone conference call where anyone can speak whenever they want to. It can only be set up as a duplex pair using a combination of two radio devices (headset, body, or compact base)- two people can speak at the same time to each other. If more than two people need to be in the conversation group, then you must order Repeater radio sets (see below)

Duplex pair - xmit "A" -> rcv "A" / xmit "B"-> rcv "B" 

This network is a special instance of the full duplex radio in which many people can be combined in a network and talk simultaneously. This is accomplished by combining a multi-man base station with "Repeater" radios (headset or body), each of which transmits on a different frequency while receiving on the same frequency (the multi-man hub handles the combining and retransmission task required for the network) Typically, groups are up to 9 people (8 remote/ 1 base operator) using one base station... but they can be larger with the addition of more base stations. (Note: Not available for ValComm)

Duplex repeater network utilizing repeater headsets and multiman base