From my understanding, you need a near field receiver/scanner, a higher end set up, not low priced. You need to be somewhat close to the radio. The radio's are not digital, although parts of them may be, when out of range, they just cut off, no static.
For the radios to communicate with each other, the same code, one of two codes (one is a number code, the other is whatever name you give your radio, so you have one numbers which is the code, the other is letters, but you have to know both for the radios to talk to each other) that has to be put in every radio. Once that is done, you can talk to one person only or the entire group of radios that have the same code. You can also send short text messages. They even have built in text such as "Can't talk now" and 5 or 10 other things if you are looking to be 100% quiet.
They are really neat radio's. I was sorry to see the company that made them go out of business.
Mine transmit about as far as GMRS radios, sometimes not as far, much depends on what's around you.
Some people say they sometimes lose sinc with each other, but it has not been a problem for me.
What I find that is so neat is that you can talk to others, and not hear anyone else. You can have 1000 of the Trisquare radios right next to each other and 10,000 bubble pack radios and not have any interaction between them or other radios. It's not like going to a big event and having people all over the channels of the bubble pack radios.
Lastly, lets face it, how many people are going to have the necessary equipment, and if they do, bother to get close enough to you to monitor what you are saying. If your some foreign agent and some 3 letter agency wants to hear you, they could easily do so, but in real life, you will be able to talk to others without anyone else hearing what you are saying. I'd say you have a 99.9% chance of no one hearing what you are saying.
There are still Motorola radios that are similar as to the voice scramble, but you sure could not buy them for $80.00 a pair with batteries, chargers, and earphones. I wish another company would slightly improve the original design of the Trisquare and start making them again for about $120.00 a pair. I'd buy more. I'm just glad I got some while they were still available. I take good care of them and they work fantastic within their design parameters. Plus, they are kinda cool.
73's John