Systems That Use Existing Electrical Cabling
The first intercom systems communicated over a set of low-voltage signal wires installed in the walls of a building. The installation was typically done during the building’s construction, but buildings could be retrofitted with communication wires, at a cost. Non-radio "wireless" intercom designs were developed that used a building's existing electrical wiring to carry communication signals. Such systems work similarly to normal wired intercom designs, with intercom stations using wires to connect to electrical outlets in rooms. This method of intercom connection is most useful in offices and homes served by a single electrical service. Products are available from a variety of manufacturers including Westinghouse and GE.
Read more about this topic: Wireless Intercom
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