What is paging in a PBX, and how do SIP paging speakers work?

What is paging

Paging is a one-way call: one person speaks, and many hear. Unlike a regular call, nobody has to "answer." The sound simply plays on the speakers.

In the past this was a completely separate system: an amplifier in a closet, wires to the ceiling speakers, and a microphone at the secretary's desk. Today, in a modern PBX, paging can travel over the same network as the phones. Every IP phone is also a speaker, and you can add dedicated speakers that connect to the network like a phone.

Common uses: calling someone who is away from the desk, announcing the start of a prayer or a class, asking a car owner to move their car, or sending an emergency message to the whole building.

Paging through the phones

The simple way to page is through the phones already on the desks. The PBX or the phone sends the sound to a group of phones, and they "answer by themselves" and play it on the speaker, without anyone picking up the handset.

This suits offices: "Whoever has the Levy file — please come to the conference room." Everyone near a phone hears it.

The limitation: a phone's speaker is relatively weak. It is heard in the room where it sits, not in the hallway, the yard or the warehouse. And if the phone is in the middle of a call, the behavior depends on the setting — sometimes the page waits, and sometimes it isn't played on that phone at all.

For the phones to answer by themselves, auto-answer for paging must be turned on in them. When the phones are configured centrally, this setting is sent to all of them together, and there's no need to go from desk to desk.

SIP paging speakers

When the page needs to be heard somewhere with no phone — a hallway, a dining room, a yard, a hall, a warehouse — you use a SIP paging speaker. It is a speaker that connects to a network cable, gets power over PoE, and from the PBX's point of view it is an extension that answers by itself.

There are several types: a ceiling speaker that fits into the acoustic ceiling in an office or classroom; a wall speaker for hallways; and a powerful, durable horn speaker for a yard, a parking lot or a noisy warehouse.

The advantage over an old paging system: there is no need for a central amplifier or separate speaker wiring. Each speaker receives the sound and the power over the same network cable, and you can add a speaker anywhere there is a network port.

When choosing a speaker, you ask a few questions: how big the area is, how noisy it is, whether it is outdoors or indoors, and how high the ceiling is. In a long hallway, several low-volume speakers are better than one powerful speaker at the end, which deafens whoever stands next to it and can't be heard on the far side. And outdoors, choose a speaker designed for rain and sun.

Paging a group — zones

You don't always want the whole building to hear. So the speakers and phones are divided into paging groups, or zones: first floor, second floor, yard, offices, the beis medrash.

Each zone has its own code or number. Dial the code for "yard" — only the speakers in the yard play it. Dial the code for "whole building" — everyone plays it together. A speaker or phone can belong to several zones.

Example: in a yeshiva, the "beis medrash" zone includes only the speakers there, to announce the start of a session. The "offices" zone includes the administration's phones. And the "emergency" zone includes everything.

It is worth documenting the zones in a simple list next to the secretary's phone: code, zone name, and what it includes. A new employee will know right away where to page, and won't accidentally page the beis medrash in the middle of a class.

How the sound reaches several places at once

There are two technical ways. In one way, the PBX opens a separate call to each speaker and phone in the group, and they all answer by themselves. It's simple, but in a large group that is a lot of simultaneous calls, and it goes through the internet.

In the second way, called Multicast, one device on the local network "broadcasts" the sound once, and all the speakers and phones listening on the same channel pick it up. This is very efficient inside the building, but it works only on the local network, and the network has to be configured for it.

Which way suits your organization depends on the number of speakers, the network and the equipment. This is a decision made during planning, not afterward.

A simple picture: in the first way, the PBX phones everyone separately, like someone notifying all the neighbors one by one by phone. In the second way, it steps onto a stage and speaks to everyone together. In a building with dozens of speakers, the difference in network load is significant.

Paging vs. internal intercom

Two terms that are often confused. Paging is one-way and to many: you speak, and it's heard in several places. An internal intercom is a two-way call to a single phone, which answers by itself on the speaker: "Moshe, can you hear me? Bring the file." Moshe can reply right away without picking up the handset.

Many phones have a key or a code for each of them. An internal intercom suits close working pairs, like a manager and a secretary. Paging suits a message to a group.

There is also a door intercom, which is already a third thing: a device at the entrance that rings the phones inside. You can combine them: a ring from the door that also plays on a paging speaker in the warehouse, so that whoever works there hears it too.

Integrating with an existing paging system

Many institutions already have an old paging system: an amplifier, speakers in every classroom, and a microphone at the secretary's desk. You don't have to throw it out.

There are paging adapters — a small box that connects to the network on one side and to the audio input of the existing amplifier on the other. From the PBX's point of view, the adapter is an extension that answers by itself; from the amplifier's point of view, it is a microphone. This way, any phone in the organization can page all the old speakers.

This is a good solution when the existing wiring and speakers are in good condition, and when you want to add capability without a big project. If the old system is already failing, it is sometimes simpler to move to SIP speakers.

Before deciding, check the old amplifier: does it have a free audio input, is it still working properly, and does anyone know its wiring. An old system with no documentation can be full of surprises.

What happens when someone is on a call

An important planning question: if you page a phone that is in the middle of a call, what happens? There are several possible behaviors, depending on the phone and the setting: the page isn't played on that phone; it is played quietly over the call; or it interrupts the call.

In most offices, people prefer that a regular page not disturb a call with a customer. But in an emergency announcement you want everyone to hear. That is why on many phones you can give paging zones priorities: regular paging at low priority, and emergency at high priority that overrides everything.

SIP speakers sometimes also have the option to play background music, which is interrupted when a page starts and resumes afterward.

Comparison: paging options

In practice, many institutions combine them: paging to the phones in the offices, SIP speakers in the yard and hallways, and sometimes an adapter for the old system in the hall.

Paging in an emergency

Paging is an important tool in an emergency: a fire, an alarm, an injured person, or a need to evacuate the building. In such a situation there is no time to look for the right code.

So it is worth deciding in advance: one short, well-known code for paging the whole building; a dedicated key on the secretary's phone and on the phone of the person in charge; and high priority for this page, so it is heard even on phones in the middle of a call.

It is important to remember that paging over the network depends on electricity and the network. If you want it to work during a power outage too, the switch that powers the speakers must be connected to a UPS. And in any case, a regular paging system is not a substitute for a dedicated alert system required by law or by fire department requirements.

Paging etiquette — so it doesn't get ignored

A page that is played every five minutes becomes background noise, and people stop listening. A few simple rules:

• Use paging only when it is really needed, and not instead of a phone call.
• Page only the relevant zone, not the whole building.
• Keep it short and clear: who, what, where. "Rabbi Cohen, to the secretary's office, please."
• Set the speaker volume for each location — loud in the warehouse, low in the offices.
• Set quiet hours, for example during prayer or a class, when no pages are made to that zone.

A field example: a chesed organization's warehouse

A small chesed organization that distributes food baskets has a small office and a large warehouse behind it. The volunteers in the warehouse didn't hear the phones in the office, and every time a truck arrived, someone had to run to call them.

Two horn speakers were installed in the warehouse, powered from the same PoE switch as the phones. From the phone in the office, you dial one code and say "Truck at the gate, two volunteers for unloading." The voice is heard throughout the warehouse, even over the noise of the carts.

In addition, the ring from the intercom at the gate was set to play on the speakers in the warehouse too. This way, even when nobody is in the office, whoever is in the warehouse hears that someone is waiting at the gate.

The only thing that needed adjusting was the volume: at first the speakers were too loud next to the packing table, and after a short adjustment they were heard well throughout the warehouse without startling whoever stands beneath them.