# New Wireless Headset System- Half Duplex



## ricc0luke (Jan 30, 2005)

I was just looking at Production Intercoms website, and I came across this new type of wireless system- Half-Duplex. There are one or two disadvantages, but it is cheaper, and if you are only using one or two wireless there are barly any disadvantages. There are also many perks too.... for instance, it does not eat up as many channels as full-duplex systems do. Below is a section I copyed from their website-


> Half-Duplex: Half-duplex describes a system which consists of simplex portable transceivers (walkie-talkies) or simplex mobile or marine transceivers, but, rather than communicating directly with each other, they talk through central transmitter/receiver called a repeater. The transceivers are programmed to transmit on one frequency and receive on another. The repeater receives all the transmissions from the transceivers on first frequency and retransmits them on the other.
> 
> The repeater is designed to transmit constantly. (Portable transceivers are not designed to do this.) A half-duplex system is primarily used to increase the range of a group of hand-held, mobile, or marine transceivers, as the repeater can be many times more powerful than the portable or mobile transceivers, and it can be equipped with a raised antenna sophisticated enough to pick up the weaker transmissions from the portable transceivers from a greater distance. Half-duplex systems are very common. It is probable that your local police, fire, and emergency services are using them. The repeater in a half-duplex system is different from the one used in a full-duplex system in that it receives only on a single frequency, so only one portable transceiver can talk to the repeater (and thus be heard by all the other portables) at a time.
> 
> ...



There is a diagram as to how they work at- http://www.beltpack.com/HD903-diagram.pdf

Cool stuff-


What do you all think? Has anyone used this?


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## ricc0luke (Jan 31, 2005)

Here is some more info simply because I really want to hear what other people think about this-


> CC. Half Duplex Systems (CLICK to open our diagram in a new browser window):
> 
> The AD913 Simplex System discussed above has four or five legitimate knocks on it:
> 
> ...


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## cutlunch (Jan 31, 2005)

An interesting system, but in a school system would it be worth the cost? From some of the prices I have seen just to setup the base station would cost about two grand. Maybe for a production company it would cut down on long cable runs. How much does licencing cost in the States.

It would be nice but if your venue is small enough you could do it with the walkie-talkies that have that caller selection thing that you can set all your walkies to the same call tone.

I might put it in a brand new facility or maybe in a multipurpose area eg. gym where you can't leave in permanent cable runs for the coms.


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## Andy_Leviss (Feb 1, 2005)

This isn't anything particularly new. Interfaces to allow a ClearCom system to broadcast via a two-way radio with the call button as the PTT button (as well as to allow the CC system to listen to the radio) have been around for a long time. It's just a small box that plugs right into the external mic/speaker/headset jack of whatever radios you're already using.


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## ricc0luke (Feb 1, 2005)

Its not the same two way radios into your existing headset system. Two way radios are simplex. When you combine them together you get half the system full duplex and half simplex all talking together. With this new system the wireless part uses half duplex (hence the name) instead of using simplex. It is not the fullduplex that the traditional wireless headsets use, but this system uses less channels- a real plus if you are using lots of wireless mics. There is more info on the differences between the systems at:

http://www.beltpack.com/howtheywork.htm


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