Multicast Paging and Intercoms
Gain a deeper understanding of the multicast paging feature, options for expanding the use of paging within your organization, and how paging differs from sending intercoms.
Written by Val Campos
Updated at April 21st, 2026
Table of Contents
Multicast Paging
When a device uses multicast paging, a voice broadcast message is sent to many IP devices via a multicast IP address. The page is transmitted to other devices connected to the same LAN (Local Area Network) as the sender of the page. The devices that could receive the page would be IP phones, handsets, and paging horns that have been set to listen to the same multicast address the page is being sent on. This is achieved by assigning this multicast address as a Listening Address for those devices.
What are Paging Groups/Zones?
Multiple devices that are set to listen to the same multicast IP address, or channel, are considered to be within the same paging group or zone. Different groups of devices can be set into different paging groups. Most IP phones and paging devices can be set into multiple paging groups.
Note: Many IP phones and devices require remote access to their interface for configuring multicast paging channels. If you would like to set different groups of phones or paging devices into different paging groups/zones, you can submit a request to our Technical Support team.
You can contact our technical support team by calling (469) 429-2500, emailing support@spectrumvoip.com, or sending in a ticket using our support website:
https://www.spectrumvoip.com/support/.
What Are Some of the Devices Used for Paging Systems?
Paging Systems can be made up of a variety of devices that have the ability to send and receive pages. These devices include other IP phones, paging phones that solely play pages over their speakers, paging horns, and analog paging devices that are connected to an ATA (Analog Telephone Adapter).
Paging Phones
As an alternative to buying and using a paging horn (i.e., a speaker), an IP phone can be mounted to a wall and configured to act as a speaker when it receives calls and pages. One of the most commonly installed phone models for this purpose is the Yealink T27G.
If you have had a phone installed in this way, our Installation team will usually assign a speed dial to your phones that will intercom the paging phone when it is pressed. This phone will also be set on the same multicast channel as your other devices, so it will receive and play pages as long as it is connected to the same internet network as the other devices.
If this paging phone is located in a different building or connected to a different internet network, then sending an intercom call to the paging phone would be used instead. This is done by dialing 08 and the extension number of the paging phone.
IP Paging Horns/Speakers
Paging horns are speakers that are used within a paging system to play a page or intercom throughout a large area. IP paging horns and speakers can be mounted and connected to your internet network to allow other IP devices, like your desk phones, to send multicast pages and intercom calls to the speakers.
If you have had IP paging horns installed, our Install team can add speed dial buttons to your phones that can intercom a paging speaker or a group of paging speakers. Each paging speaker will also be set on the same multicast channel as your other devices by default, so it will receive and play pages as long as it is connected to the same internet network as the other devices. If needed, each paging horn can be assigned to different channels if they should be in separate paging zones.
If an IP paging horn is located in a different building or connected to a different internet network, then sending an intercom call to the paging phone would be used instead of multicast paging. This is done by dialing 08 and the extension number of the paging horn. To make dialing the paging horn more convenient, a speed dial button can be added to phones that should be able to intercom through this speaker.
Analog Paging Devices
If you have a legacy, analog paging system in place, your analog paging devices can be connected to an ATA (Analog Telephone Adapter). The ATA would convert the analog signaling of the analog paging devices into VoIP signals so that the paging devices can utilize VoIP features, like multicast paging.
How Can Multiple Off-Site Devices be Paged Together?
To allow devices from multiple locations to be paged together, a conference bridge can be created and configured to place intercom calls to a set of devices that are assigned to it. The devices that can be paged through this method include IP phones, IP paging horns and speakers, and analog paging devices that are connected to an adapter.
Our team achieves this by setting the conference bridge to dial the extension numbers of a set group of devices with the 08 feature code (i.e., the intercom code). These devices are set as permanent participants in the conference bridge so that anytime the bridge is dialed, the same devices receive the intercom call each time.
For example… There is a warehouse in a building that has paging devices connected to an internet network that is different from the phones. This example warehouse has two paging horns with extension numbers 300 and 301.
In this example, our Technical Support team created a "Page Warehouse" conference bridge with the extension number 6000. This conference bridge would be set to have these devices as permanent participants. The conference bridge would be set up to intercom each horn by dialing 08300 and 08301.
Now one of the users in a different building can dial 6000 to intercom the paging horns.
If there are multiple groups of devices that need to be able to page each other in this way, a separate paging conference bridge can be created for each group of devices.
Note: If you would like paging conference bridges to be created for your paging devices that are off-site, you would need to submit a request to our Technical Support team
You can contact our technical support team by calling (469) 429-2500, emailing support@spectrumvoip.com, or sending in a ticket using our support website:
https://www.spectrumvoip.com/support/.
While requesting this change, you should include the following information:
• A list of the devices that should be paged together, such as any phones, paging horns, paging phones, etc.
• A preferred extension number for the conference bridge that will be created.
– If one is not provided, the conference bridge will most likely be given an extension number in the 6000s range.
• A preferred date and time to test the change with a Support Analyst.
• The extension numbers of any desk phones that should have a button added for paging this way.
• A preferred spot on the phones to use for the button that would call the conference bridge.
To start a page through this a paging conference bridge, you would dial its extension number from a desk phone or handset.
If Technical Support was directed to add a button to phones for using the paging conference bridge, you can press the BLF button they created to dial the conference bridge as well.
Intercoms and the 08 Code
Using the 08 code to start an intercom call works differently than multicast paging. With an intercom call, an actual SIP call is initiated between two devices. When the receiving device gets the call, it is prompted to automatically accept the intercom call and play its message over its speakers.
One of the feature codes you can use by default on your desk phone, handset, or softphone is the 08 code. When you dial 08 and a user's extension number, an intercom call is initiated between the phone you used and that specific user's phone. This is one of the main ways you can page individual devices separately.
For example… If 08100 is dialed on a phone, the phone with extension 100 receives an intercom call over its speakers or receiver if the receiver is off its hook.
Create an Intercom Speed Dial
You can make sending an intercom to an important device more convenient by creating a speed dial button for your phone. To do so…
- Log into Stratus.
- Visit the Inventory page of Stratus.
- Click the Phone Hardware tab to view your phones.
- Click the MAC address of the phone you want to add this button to.
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Click an unassigned button and use the Select a feature dropdown to select User (BLF).
WARNING: For many phones, line key 4 or 5 may be set as the main multicast paging key that pages all devices on the same internet network. Multicast paging keys will appear as unassigned since they are added through scripting on the phones.
Before selecting an unassigned key on the first page of a phone, it is recommended to check the display of the phone itself to see if one of these buttons may actually be a PAGE button.
- In the Enter a number box, type 08 and the extension number of the device to intercom.
Quick Tip: You can use the extension number of a coworker's phone, a paging phone, a paging horn, or an ATA that an analog paging device is connected to.
- In the Label box, type a name to show for this button on the phone.
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Save and resync the phone to apply and see the button change.
✔ Once the phone has updated, you can press the new speed dial button to start an intercom with device assigned to the extension number dialed after the 08 code.