Wired Intercom System: Key Questions to ask Before Choosing One

This section aims to clarify the complexities you'll encounter while searching for the right intercom or door phone system. Here, we briefly explain the underlying technology behind each system and outline their pros and cons.

Master to Substation Intercoms

Some systems feature a "master" station that can call multiple substations, while substations can only call the master station, not each other. In some cases, additional master stations can be added to call each other, but this requires installing cables with more wire pairs for multiple communication channels. Systems like the Cat-5 system described below treat all stations as master stations, allowing calls to any station.

In voice communications, there are half-duplex and full-duplex methods of transmission and reception. Half-duplex communication, like that of push-to-talk "walkie-talkie" radios, requires one person to press a button to speak and then release it to listen, preventing simultaneous conversation. Full-duplex communication, as used in telephones, allows all parties to speak simultaneously. Our 2-wire master to substation intercoms use half-duplex communication, but the person at the substation doesn't need to press a button to talk.

Cat-5 Intercom Systems

Cat-5, short for Category 5, is a type of bundled wire typically used for data networks, consisting of four twisted pairs of copper wire. These systems often use internet protocols and can operate on existing networks or as self-contained systems. Cat-5 intercom systems, which use this wiring, generally offer more features due to digital communication between stations. Cat-5 wire is widely available at building supply stores since it is routinely installed for computer and telephone networks.

Handset to Handset Intercoms

Basic 2-wire handsets can be used to communicate directly with each other. Lifting the handset on one side rings the other side. Some systems support more than two phones, causing all connected phones to ring simultaneously.

Phone Intercoms

A phone intercom uses analog or VoIP telephone lines to make calls when the handset is picked up. Also known as "hotline intercoms," these systems call a specified phone number when the handset is lifted, and they work with both analog and VoIP telephone systems.