Intercom
System Design
This page describes the points to keep in mind when designing an intercom system.
Device
There are four main types of devices. Basically, a system is constructed by combining these.
1) Exchange, 2) Master Station, 3) Sub Station, 4) Interface
1) Exchange, 2) Master Station, 3) Sub Station, 4) Interface
1) Exchange
Exchange is a device that connects each station.
* Nowadays, each station is connected to a network, and in some cases systems without Exchange or network servers play this role.
Exchange is a device that connects each station.
* Nowadays, each station is connected to a network, and in some cases systems without Exchange or network servers play this role.
2) Master Station
A device that allows a user to speak and listen to the other person's voice. A master station has multiple keys and can call many stations.
A device that allows a user to speak and listen to the other person's voice. A master station has multiple keys and can call many stations.
3) Sub Station
This device is your station, but it differs from the master station in that it can often only call one party. Substations are selected when system administrators and operations administrators do not want to give users too many operational privileges.
This device is your station, but it differs from the master station in that it can often only call one party. Substations are selected when system administrators and operations administrators do not want to give users too many operational privileges.
4) Interface
This is equipment used when connecting with PA systems, security systems, or other intercom systems.
This is equipment used when connecting with PA systems, security systems, or other intercom systems.
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For example, if the interface is connected as shown on the left, the master station will be used like a PA microphone.
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System Stracture
There are about three types of systems. These can of course be mixed. If the designer has an idea of how the system will be used in advance, it will be easier to design the system and provide instructions to users.
Master-to-Master system
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This configuration is used when each user calls freely, such as in an office. Many master stations are arranged and can be freely connected to each other.
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Master-to-Sub system
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A structure in which many substations call a master station.
For example, this configuration is often seen in entrance control systems and automatic ticket vending machines at stations. 
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Paging/Broadcast
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This is a configuration for broadcasting widely and unilaterally like a PA system. Although they are often more expensive than regular PA systems, their advantage is that users can specify the range of broadcast destinations in detail.
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Connection
Analog Line / Network
Designers must decide whether to make analog or network connections between devices.
Network (LAN etc.) is easy to connect and requires fewer wires. Also, IP-type stations may not require Exchange. On the other hand, remember that the system requires a switch every 100m.
Analog lines tend to have a large number of wires, but long distances can be wired using only wires. Running costs may also be lower than maintaining network infrastructure.
Designers must decide whether to make analog or network connections between devices.
Network (LAN etc.) is easy to connect and requires fewer wires. Also, IP-type stations may not require Exchange. On the other hand, remember that the system requires a switch every 100m.
Analog lines tend to have a large number of wires, but long distances can be wired using only wires. Running costs may also be lower than maintaining network infrastructure.
Analog Line and Exchange
When choosing an analog line, pay attention to the following three items.
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(1) How many stations can be connected to Exchange?
(2) How many stations under Exchange can talk at the same time? Please note that this may be less than (1). (3) Wiring type and maximum distance. The resistance of the wire often determines the maximum distance. |
