While the obvious solution is to use wireless doorbells, all set to the same digital code for the button, I still prefer the good old fashion electromechanical ones.

Hopefully, bus driver's suggestions can help solve the problem.

While I have used wireless in the past, I'm not a fan of wireless when wired is possible to do. I always had trouble with the unit actually playing the tune if the button wasn't held down for about a second or so. Plus the batteries seemed to need replacing more than I felt was reasonable. And I don't have outlets in the places I'd like to put doorbells for the plug-in wireless models.

This is in a home at the stud stage (new construction), so I want to add the wiring now to support what's needed later. We haven't picked out any doorbells (or buttons) yet. But what I'm doing is running 18/5 from each doorbell *and* doorbell button location back to my mechanical room. There I'll add any needed transformers and terminate as needed.

I did call both IQ America (Home Depot brand) and Craftmade (found online) as I had seen a couple of nice looking bells (probably chimes in reality). I asked them both if I could install their products (4 chimes) with a single front-door button (I think either brand, as well as probably others, would be okay if nice looking - our decor is more contemporary, so if we found something that looked good, we'd go with it). However, both companies said no-go. They said that I could do up to 3 chimes. But that leaves either my garage or shop without a chime/bell.

I know that doesn't answer the question thoroughly, but I'm not sure what to provide at this point, but want to make sure I run the appropriate wiring if something different is needed to support my goals (4 bells *or* 4 chimes - all the same if needed).

Due to family medical issues, I must leave right now. Use 18 gauge wire. Check it to be sure. Some of the stuff out there is really 19 gauge and marked as 18. Check it with wire gauge or micrometer. Some installers use telephone station wire of 24 gauge. If you do that, your plan will not work for sure. The Nutone 301T transformer is now obsolete from Nutone, but some sellers still have some at widely varying prices. Shop for best price and get one of those if you are using chimes.

I'm using 18/5 from Home Depot (hope it's really 18 and not 19 gauge), but I don't have a micrometer (my brother does, but he lives in another city - guess I'll ask him to bring it down next time just in case). I didn't want to use anything smaller as I prefer to oversize in case needed later on. It's going to be impossible to change out wire once the sheetrock goes up. I appreciate the Nutone 301T transformer information. A quick search shows you are exactly right. Some places have them (only 1 or 2) and at varying prices. As much as I'd like to order one now, I'll wait until we decide on the doorbell to make sure they are all 16 volt, but this seems like a good one!

Hey, really hope your medical issue turns out okay - thanks for taking the time to respond!

Plan the transformer location for easy access in case some experimentation is necessary later. The 301T is 16 volts. If it proves to be inadequate (weak), an 18 volt transformer can be tried if there is room provided for mounting it properly. But the 301T works great for 3 chimes, each mounted on different floors of the house.

To restate the obvious, 4 chimes with one switch (button) involves 4 times the current draw of 1 chime and about 4 times the length of conductors. The problem, if there is one, will be voltage drop. One chime on 24 gauge operates very weakly due to voltage drop. While it seemingly violates one Article in the NEC, the 18-5 cable could be used with some of the conductors in parallel, such as using the two extra conductors for pairing to make just three operating conductors, two of them paired, for the chime system. I would not hesitate to do so.

If the 16 volt transformer does not properly power 4 chimes, one could try a RB570 18 volt unit intended for gate operators. Shopping for price can be worthwhile as prices for the RB570 vary widely.
But try the 16 volt first.

I have tried wireless in the past and the range was not good for the 2 models I tried and returned.

I don't know how much money you want to spend, but I purchased for about $300, a system where you have one doorbell, and 2 TV monitors. CAT5 cable was run to each area. Each tv monitor needs a transformer. We put a 'hidden' spot in the garage where all the transformers plug into a double duplex using a plug in strip to give them more room since transformers are wider than a plug size. We basically got some 18g 2-wire and ran that from each tv monitor location to where the 2gang duplex would be in the garage. Then after drywall went up, the transformers were cut and spliced into the 2-wire that went to the tv monitors. Each monitor needs a separate transformer according to the Lone Star people. since you would use 4 locations, they might have something where you just use a couple tv monitors (expensive) and a cpl locations that can just do 2-way audio.

This system is also available in a 4 monitor. It was a Genway brand which is sold by a company in Houston, TX. They have real live phone support and were nice. They also have a store on Ebay, but if you buy direct from them like I did, they gave me a discount since they didn't lose money through their ebay fees. They are called Lonestar Group. but there are other companies (google video door intercom).
See link.

I liked the look and feel of the DNS7 doorbell/camera. If feels heavy in your hand and I have gotten a lot of compliments on it and I live in San Francisco where people are very style conscious. Both the plumbing inspector and the Glass Installer asked me where I got my doorbell.

However the angle of the camera is not very wide so if people are not standing right in front of it I can't see them. There is 2-way audio so you can ask them to step back.

My system was $300, but they are able to give you a package with more monitors. Just call them on the phone to ask. Their tech support can even explain about how to cut the transformer wire and splice it so you can run it longer through the walls. But it's really simple. We did not do any splicing in the wall. We did it outside in the garage where it is accessible.

Here is a link that might be useful: Lone Star Video Door Intercom

to clarify - the CAT 5 wire run was for the "video" connection between the doorbell camera and the different tv monitors. you need a home run from the doorbell camera to each of the other locations.

You still need to run the 18g for the power from each tv monitor to the location in say the garage where you have a duplex with a surge protector strip for the transformers to plug into. I like the system I have - my only complaint is the small angle of the camera - but it is better than no camera and the audio is very nice. Sometimes I use it to tell the UPS guy to leave the package at the door since I don't want to run downstairs right away.

Also, since you are in the rough now - might I suggest running some CCTV wire for a future camera system?
I bought a cheap starter system from tigerdirect - it came complete with 4 cameras and a recorder and you can put it on your internet to spy on your house when you are not home (nightowl was one I got but they have others).
I did not use the free wire that came with it. I wanted good wire in the walls before we closed since the cameras I can always upgrade later. I went to my local electrical supply shop and bought a full roll of RG59/pwr line called siamese since it has 2 wires bundled together. It basically has an RG59 cable bundled with the power line and is officially used for CCTV everywhere. The higher quality wire will give you better reception and less noise. I also had to buy connectors for ends of the RG59 and the power line in cameras. I did connections after all the walls were up and got the connectors on amazon for cheaper than my local shop. I regret not running the RG59/pwr cable to more locations so that I could later expand to an 8 camera system. Here is a link to the Siamese cable: http://www.cablestogo.com/product.asp?cat_id=317&sku=43113
they probably have connectors to cameras too.

Thanks for all the suggestions. As stated earlier, wireless is a no-go for me since I can run wires now as needed. If the house were sheet rocked, that would be a much different story. Kisu, I looked at the Lone Star video link and it looks interesting. My only concern at this point is we are installing (it's already roughed in with wire and double-gang mud rings) a whole house "selective call" intercom. This system is also wired with CAT5/CAT5e and comes with a front door button. When I originally posted the question I had forgotten that the intercom had a front door button that "rings" all intercom units. There is no video, but we have siamese wire to the front door too (above and to the side of the front door) for a camera at this location. It made me realize we need to include the CAT5 and double-gang outdoor rated box for their doorbell button. And it can even ring interior doorbells if desired, so I'll also still run the wire. Might be nice to have it ring a phone too, but no-go per the vendor.

You could put relays in your mech. room.
One for each bell/chime, and all operated
from one button, or even a second button
at the back door.

Relays could be used if desired. Relays use power, possibly more than the chimes will use. So power supplies (transformers) become even more an important consideration.

Call the Lone Star people - at the least even if you don't buy it - they can give you free advice on the possibilities - so at least you will have all the wire in the walls for "future" possibilities.

the main guy I talked to there didn't know as much - but I asked to talk to the tech support guy and that was helpful.

If you are in the Houston area - they do the install too, but I did it myself with a helper - using their directions and phone support.

I am a little confused now though - from the sound of it did you already buy an Intercom system? Can it be returned if it doesn't support ringing in 4 locations like you want?