Snom PA1 Warning System Overview
IP-telephony is not only obvious and well-known devices, such as automatic telephone exchanges and telephones connected to it. A telephone communication system may include devices that provide not communication between subscribers, but a completely different interaction, which we often encounter and which we simply don’t notice. Here, unobtrusive music plays in the elevator of the shopping center, in the supermarket they announce discounts and new products, in the bank branch a pleasant voice speaks the number of your electronic line, the teacher conducts a seminar for a large audience, the theater sounds a “third call”, the announcer announces boarding your plane, at the enterprise, employees hear a voice announcement. Finally, a situation in which I wish you never to be: warning visitors and employees about an emergency and demanding to leave the building.
All this is possible thanks to warning systems and speakerphone.
In any organization where you want to make announcements for staff and visitors, you have to think about how this will be done. You can do it the old fashioned way - hanging up pieces of paper, you can shout at the “matyugalnik” or ring the bell. But modern communications simplify this task. Almost everywhere, starting from a small office for a couple of dozens of people to the hotel complex, IP-telephony is used. Therefore, it is logical to build an alert system on its basis. This article will discuss the Snom PA1 device, which is a turnkey solution for loud alerts.
Snom PA1 is an IP module that combines a SIP subscriber device and an amplifier. A small (160x120 mm) and durable "audiophile" case made of anodized aluminum weighing about 200 grams can be hung on a wall or ceiling. The compact size allows you to hide it from the eyes behind the false ceiling or in the distribution panel.
On the sides of the case there are cracks into which “ears” are inserted for attaching PA1:
PA1 is an entry-level device, it does not have a wireless interface, and you can connect only one speaker. A 10/100 megabit dual-port router allows you to connect several of these amplifiers to each other and connect a webcam. The Multicast protocol is also supported, with which you can set the broadcast to a group of several PA1 modules. A Class D digital amplifier has a power of 4 watts and any speaker suitable for public address systems can be connected to it.
At one end there are two Ethernet ports, one of which can supply power directly through a network cable (PoE). There is also a connector for a 5-volt power supply (not included). On the left are the reset / receive IP button, as well as two LEDs used to indicate the operation of the device and display the status when it is configured.
On the other side are the terminals for connecting the speaker and headset jacks, which, together with a special DTMF keyboard, can be used to configure PA1. An interesting way is implemented to determine the current IP address: you need to click on a special button and the amplifier will say the address in the connected headphones.
In addition, PA1 has several flat multi-pin connectors, the functions of which are assigned via the web interface. They are usually used to interface with alarm and video surveillance sensors. The web interface allows you to set the IP address of the amplifier, configure the password for access, change the speaker volume and update the firmware.
Using PA1 is very simple: just “call” it from any phone or computer connected to the IP-telephony network and say the desired announcement into the microphone.
The main advantage of Snom PA1 in comparison with traditional warning systems is the price and ease of deployment. Traditional systems require laying individual cables to the installation site, which translates into a decent amount. And in the case of PA1, the device itself is worth it as a relatively inexpensive smartphone, and you can install it wherever a regular twisted pair cable has already been laid.