Hosmart Full Duplex Wireless Intercom System, Two -Way Communication for Home and Office，Hands Free, Portable intercom, with Crystal Clear Sound, 1000 feet Range（Incompatible with Previous Version）

I purchased a set of these intercoms to take the place of my older, non-working, wired intercoms. Those would have been over $900 to replace, so I went for these for a savings of $$$! I was not disappointed in the least. You can read the information that the manufacturer supplies, so I'll just add the additional info here. Range was VERY good. In fact, if I could have had a way to check them at 1000 feet, I feel confident they would have worked. As it was they worked from inside my house all the way to the corner of my property which is probably 600 feet. I did test them from my house to barn (about 350') and did have some issue with reception in my barn, but that is very likely due to the foil insulation under the metal siding. However, everywhere in my house they worked flawlessly. I can use it from the barn to house, but just have to have it in the barn window so the reception is not blocked. Another feature that is NOT mentioned on Amazon is the fact that if I press the "Group" button, I can talk to family members in their rooms without them having to press a button to answer. This is extremely handy. The only downside would be that it does automatically transmit to ALL the units that are set up with the master unit, but that is not a problem for me. If you want to "Call" just one room, then press that call button followed by the unit number and then it will ring and they'll have to press the call button in order to answer and talk to you. Another feature that I LOVE is the fact that since they're DECT, you can have a two way conversation without people having to take turns to talk. Basically it's just like talking on the phone. I included a picture of the back side with the battery compartment and I've confirmed both with their tech department and the instructions that it can run from an 18650 lithium battery (NOT INCLUDED) and it will also charge the battery if installed (this things gets it's power from a USB to micro USB standard power cord). I'm thinking about getting some 18650s so that way if I want to I can unplug the device and take it to the couch with me and talk to other family members from there. In fact, the instructions say that it will last up to 1 week on an 18650 battery. IF you are thinking about getting these, beware that you can only have ONE master unit working with a set of one or more sub units (i.e. you cannot use a second master unit as a sub unit). So keep that in mind if you're going to buy several sets that you only need one master unit with up to 5 sub units that can go along with it. Also, one last note is that the "monitor" button functions exactly opposite of what you might expect. If you want to "monitor" a room (i.e. you listen to the sound that is happening at one of the units, but that unit does not play back any sound you make) you have to go to that room and press the monitor button AT THAT UNIT, then you can listen to the sound at a different unit. My old intercom system allowed me to press the monitor button in the kitchen and listen to what was happening in my kids' room. This one would require me going to the kids room first and pressing "monitor" and then returning to the kitchen to listen to what was happening. Not a deal breaker, but just something I thought should be pointed out. That being said, a set of these units could very easily be set up to use as a very handy baby monitor. All in all, unless you need the even longer range of the walkie-talkie type units that they sell, I would highly suggest these DECT units for every day usage around your house and property.

I liked quite a bit about their less expensive units (HY777) when I read the description: 1st, they reach throughout the house, and out into the shop (40 feet from the house), no problem. The sound was no symphonic stereo system, but clearer than the old models I had in the 80s. 2d, The group button to talk to everyone, or the talk button to talk to just the units on any one channel. 3, The call button so everyone or just one unit would hear I was trying to reach them. 4 The monitor button, so we could use it to hear what was going on in the kitchen, if I was out in the shop. All that and at only fifty something bucks for both, was too much to pass up. . .Then I got them . . no set up, plug them in, and off and running . . UNTIL I realized the volume adjustment controls did not work . . a BIG bummer, since the call button tone could raise the dead, (but was kinda handy in the shop), and the talk volume was too low . . . I fiddled n fiddled, and then threw my self to the wolves and emailed the vendor . .MIRACLE OF MIRACLES, the guy emailed me back (!!) within a day . . and said "Yes, they had some units doing that, that they were defective, and they wanted to make up for my issues by sending me a NEW UP graded unit . . no BS, no "it's your fault", no "send it back", blah blah blah . . . I darn near fell off the chair . . he said order a new unit, (these HY-616) I did, and they gave me a refund through Amazon for the WHOLE MESS . . somebody in that company takes customer service very seriously . . so 4 stars for the unit, because if the volume control worked, it was everything they said it was, and 20 stars for customer service, Thanks Adward, nice work . . for the record, he said the older models with volume controls that weren't defective were very popular, and from the reviews, I believe him.Then I get the upgraded HY616 units, and in ADDITION to everything the HY777 models could do, they are 2 way vox, so after I hit the button, they talk to me, I talk to them, and the units switch back and forth without either of us touching another button . . and the volume control works, and the sound is better than the first one . . so I recommend the HY777 if they are enough for you, but I also recommend the HY616, if you like hands free duplex like communications . . kinda like a dect 6 phone without the phone . . . Oh happy days . . . and Thanks again Adward, not sure how to pronounce your name, but I sure appreciate your customer service attitude. . .Couple of other things:It kind of fooled me at first but you need to press call and then the number of the unit you are calling.IF the master and the slave are not on the same channel, the hands free duplex vox thing doesn't work.The units are small, so pretty light, and I am not fond of the antenna sticking up, but if that is what makes them work from back in the shop all the way into the house and living room, I can live with it.The battery thing might be a good idea if you were using them from car to car, but I prefer walkie talkies.These units come with their own a/c adapters, OR you can use batteries, or large battery pack, but if you can find a cigarette lighter adapter with a 5 volt 1 amp plug that'll fit them, you're good to go in the car too . . It does hold an 18650 battery if you get the flat ended one . .

I highly doubt Hosmart had my application in mind when they made these units. I work in the control room of a cath lab. The integrated communication system is just terrible. Push to talk only and you cannot hear while talk is enabled. Very difficult to use when things get hectic. The hospital isn’t interested in changing the system so I went looking for alternatives.Basically I need a system that allows 2 way communication without having to push a button and without muting the other unit while talking. Also I needed a battery based system to keep from having “unauthorized” equipment plugged into the cath lab plugs. This system works almost perfectly for what I needed. I got some 3400 mah batteries and have used the system during 2 cases so far.The speakers and mics allow for clear, real time communication hands free even through the lead shielding of the control room. As long as the speaker is either speaking up or is fairly close to the unit, the other unit will pick up. It’s pretty great to be able to talk without having to button push or shout into the room through a closed door. My only complaint is that there isn’t a mute button. Sometimes people get rowdy I’m the control room and I’d like some way to shut off transmitting without having to end the “call” and then call back. Other than that, I’ve been very happy.