Self-Installing an Apartment Video Intercom System
Here’s how we researched, sourced, and self-installed a video intercom system for a small condominium, and so can you.
During this project, I found it really difficult to find information about the different products we used, so this blog post is chock full of text for the search engines to pick up. Read on for some adventures in low-voltage wiring.
Disclaimer: Intercom work should only be performed by authorized and qualified personnel. Anyone using the information contained herein does so at their own risk and shall be deemed to indemnify the author from any and all injury or damage arising from such use.
The Status Quo — Crappy, Push-to-talk, Push-to-listen Intercoms
Our building was built in the mid-2000s and came with a standard, run-of-the-mill audio intercom. You know, the type where pressing the button outside causes a “warble tone” in the unit, and you must push a button to talk, then press another button to listen. If the person on the other end is deemed worthy, you can press a third button to trigger an electronic door release, allowing them entry.
These systems use century-old telephone technology to amplify and transmit the various audio signals, and can be installed in 3, 4, or 5 wire configurations. Ours was a PK-543 by Tektone. It runs on 16 volts AC, and requires home runs of cable from the door panel and all the unit panels to a central device called the amplifier.
Obviously these audio intercoms are an exceptionally poor user experience, and if you’re not pressing the right button at the right time, you can miss large chunks of the conversation. You also can’t see who is at the other end of the line, which is problematic for several reasons, security being the most important. But they are cheap, simple, and generally reliable, which is why they are so ubiquitous.
The Limiting Factor — Wiring
There are a lot of fancy, new-fangled video intercoms these days, but many of them are IP-based. This means they are really little computers that need to communicate over network wiring. Our original audio intercom used CAT3 cable (think old-school phone wiring), which is not capable of supporting IP signals, so these fancy systems were out. More specifically, we have a home run of CAT3 cable with 4 twisted pairs from each unit to a central location in the basement. The existing intercom was a 4-wire system, so each panel was only making use of two of the four pairs.
Why not just run new wires? It would involve opening the walls in several places, including in each unit, which would have been messy, time-consuming, and expensive. It just isn’t feasible unless your building was designed to have easy to access crawlspaces and wire chases.
So, the task at hand when we began our research in early 2020: Figure out if there are video intercom systems that will work over our existing CAT3 cables.
The new system would also need to allow for remote unlocking of an electric door release, but this is pretty standard functionality for any intercom designed for apartment buildings.
2-wire Video Intercoms are a Thing!
Some research online revealed that there are indeed intercom systems that can transmit video, audio, and data over a 2-wire bus. There are requirements for the thickness of cable that should be used, but it’s possible to combine the 4 pairs of smaller wires in a CAT3 cable into two larger groups of wires that will work for this setup.
The three popular 2-wire systems we looked at were:
Golmar GB2
https://www.golmar.es/products/gb2
Golmar is a Spanish company and was the first system we found. The PDFs for the installations are readily available on their website. It’s pretty easy to get familiar with various system configurations and imagine what it would take to get it installed.
These systems are distributed in the U.S. by a company called Alpha Communications, and of the three systems we looked into, this one seemed to be the easiest to procure here in the U.S.
Comelit
https://pro.comelitgroup.com/en-us/product/IKALL
Comelit is an Italian company, and had a 2-wire video offering similar to Golmar’s, with one big differentiator: They have a unit panel that has built-in wifi, and can communicate with a mobile app. This means residents can be notified that someone is ringing their unit when they are not home, and they could see the video and remotely unlock the door from their mobile device. We were really interested in this feature, but in the end we were turned off by abysmal reviews of the iOS and Android apps, and didn’t want to end up stuck in the same boat as LOTS of unhappy customers.
They also make you register and sign in just to download product documentation, which was a turn-off.
Hikvision
https://content.hikvision.com/2nd-generation-intercom-homepage
Hikvision is a Chinese company, and their 2-wire system seems to be more modern than the other two we looked at. There also seem to be a lot more videos and resources online created by happy Hikvision installers. However, Hikvision is currently subject to sanctions by the U.S. government, the equipment seemed like it would be more difficult to obtain, and the single unit panel they offer seemed a bit clunkier/bulkier than the other options. This system could also communicate with mobile devices, but instead of being decentralized, where each unit panel talks to that unit’s wifi, it would have required an internet connection on the central unit. (this is something we could have provided, but it also means more potential for technical support issues in the future)
To my surprise, there is a dearth of online content about video intercom installations. Given that half of the planet is urban, you would think there would be many thousands of youtube videos and blog posts made by the firms that sell and maintain intercom systems in multi-unit buildings. Google “Golmar GB2” or “Comelit 2-wire” and you’ll see what I mean.
We ended up being most interested in the Golmar GB2 system, as it was easy to find online retailers to sell the parts, easy to design a system, and would be easy to install. It’s 100% offline, which means we give up some of the bells and whistles, but won’t have to deal with internet connection or configuration issues. Once you get it working, it should just work.
Testing It Out
Before spending a lot of money on a full system for 8 units, we bought the bare minimum equipment necessary to test it out on our wiring. This meant purchasing the entry door video panel, the power supply, a bus-splitter, and one unit panel. The people at supplycounter.com actually contacted us to confirm the order since it wasn’t a complete system (see their note below).
If for whatever reason it didn’t work, we’d be out about $600. The items were non-returnable, so we’d either eat the loss or try to resell them on eBay or whatever.
Fortunately, it did… we tested it on the longest run of cable, 4 stories, and it worked like a charm! We could initiate a call from the basement to the 4th-floor unit, and they could see the caller and trigger an unlock.
We weren’t ready to source the whole thing yet, so in the meantime we set up a little demo board so other residents could see what using the system would be like.
Putting it All Together
Golmar’s modular system has several options for the external enclosure and panels. We sprung for the stainless steel, as it would be the most durable and best-looking of the options. This would end up costing us time, as the parts had to be shipped in from Spain. I guess they don’t keep an inventory of these in the U.S.
We designed a 2x2 panel configuration. The left two panels would house the main camera/audio module, and a button extension module. The panels on the right would be modified to accommodate additional features:
- An Access Control Reader — An RFID reader for access control means that residents can trigger the electronic lock release with a key fob instead of using a physical key to unlock the door. It’s more convenient, but the real benefit is control over who has access, and the ability to revoke access if someone loses their FOB. You can’t do that with physical keys. More on this later.
- A USPS Arrow Lock Switch— This is how the postal delivery person can gain access to the building to deliver the mail. It’s just a special lock and a switch that triggers the electronic door release. We could have installed it in a separate box and connected it to the system with a short piece of conduit, but it wouldn’t have looked as nice and would have been a bit more work to install.
A Custom Baseplate for the Unit Panels
The original panels were in a portrait orientation, attached to the wall with a metal bracket. The new video panels (Golmar VESTA7) were in a landscape orientation, and installing them over the same wall box would have left an unsightly strip of unpainted wall, or a line where new paint was added around the original box.
To remedy this, we ordered custom-sized white acrylic panels from acmeplastics.com to place behind the new panels. They provided a 1" buffer around the new panel’s dimensions, and were sized specifically to just cover the footprint of the original panels.
These panels ended up being a nice visual touch and provided a very clean installation for each of the units that wouldn’t require any painting or wall patching work.
Programming and Testing
Once the deliveries arrived, we set up everything in a local installation to make sure the panels and buttons were configured correctly. The configuration is all done with DIP switches on the unit panels. Each button the door panel calls a specific address, all you need to do is set the DIP switches to the corresponding address.
We had to drill some holes in the blank plates and do some custom modifications to fit everything into the housing, but were able to get everything in order in a matter of a couple of evenings. Everything in the panels was pre-wired for quick connection with wire nuts once we actually installed it at the main entrance.
The installation went smoothly… the panel enclosure required making 4 holes with a hammer drill, routing the wires into the back of the box, and hooking everything up.
The wiring from the building is pretty simple: 12 Volts DC from the basement powers the access control reader and the electronic door release. A two-wire bus (over CAT3, just like with the unit panels) powers the audio/video panel and carries the signals. After removing the old panel, tidying up the wiring a bit, mounting the new enclosure with some concrete anchors, and connecting everything, we were in business!
In the basement, we installed the power supply, unit panel splitters, a 12 volt power supply, and an Uninterruptible Power Supply (battery backup) to keep things running for a while if the power ever goes out.
The actual panel installation required a visit to each unit, which we coordinated ahead of time. Each unit install only took about 5–10 minutes, and we communicated via walkie-talkie between a crew doing the installation in the units, a crew making connections in the basement, and performing test calls from the entrance door. Because we prepped and tested everything beforehand, the actual installation only took a few hours.
Access Control and Key Fobs
We were interested in access control with key fobs for a few reasons. One was to get away from physical keys. Residents and vendors always need copies of door keys, they get lost from time to time, and it’s just hard to keep track of who has them. It’s also pricey and logistically hard to get copies made of the high-security keys we use.
Another reason to go with key fobs is convenience, as they allow you to unlock and open the door with only one hand free, which is helpful if you are carrying something or pushing a stroller.
I’ve messed with access control systems, in a previous life, and they always required readers that can talk back to a central processing unit that keeps track of all of the logic. Usually these require clunky windows software to configure. Sometimes they need to be networked and connected to the internet. We wanted something that was dirt-simple to configure, and after asking around, someone recommended Paxton’s Compact line of access control readers.
Paxton’s Compact series look like ordinary RFID key fob readers, but they operate in a standalone configuration. This means we don’t need to worry about power and wiring for a central processor, everything is local to the door that is being controlled! Best of all, there is no programming. You just order key fobs in batches of 10. Each batch comes with a special card that you pass in front of the reader to authorize all 10 fobs, and each fob as what is called a “shadow card” to revoke access to the corresponding fob if it is ever lost.
It’s a brilliant system that provides all the benefits of RFID access control without all of the complexity!
This was pretty easy to connect to the Golmar intercom, which has a dry contact door release. Instead of being directly connected to the electronic door release, the reader is first connected to a 12V relay. When someone presents a valid key fob, the relay is activated closing the dry contact terminals on the intercom panel and unlocking the door for 5 seconds.
The rub: It was really difficult to source Paxton equipment online. Their website and documentation makes it really easy to figure out how their products work, but you can’t just buy the stuff on Amazon. They have a network of authorized distributors, many of which list the items online but won’t sell to you unless you are an installer or dealer. Many of the dealers won’t sell to the general public either. ¯\_(ツ)_/¯ When we finally found an online vendor to order them from, it took several weeks for anything to arrive since the items are all drop-shipped from the manufacturer. I love these products, but wish they were less restrictive about distribution.
Voila!, a Retrofit Video Intercom
I gloss over a lot of the technical bits, but none of this is difficult if you have a basic comfort level with wiring and electronics. Mostly, I want to let people know that it is possible to retrofit your audio intercom with a video intercom for less money and effort than you probably thought. Thanks for reading.
