Phone VoIP (SIP) adapter: pros and cons. What is a VoIP adapter and why is it needed Which VOIP adapter to choose

A VoIP adapter is a device that is used to connect landline phones to an IP network. The work uses the SIP protocol, due to which the devices are often called SIP adapters. Standard basic models have three connectors that allow you to connect a landline telephone, the Internet and a computer (laptop or system unit). As a result, a simple phone can join the Internet without requiring the purchase of a new IP phone. Some models have two FXS ports for connecting several landline phones.

Features of using adapters

The VoIP telephone adapter is classified as SOHO (home/small office), so such equipment falls into the affordable price range. Unlike a VoIP gateway, adapters use a more simplified processor with little processing power. The functional part of the devices (gateway and adapter) are similar to each other. When you connect a landline phone, it is assigned an IP address.
VoIP equipment has a single goal: converting the voice stream into an IP signal and back (for incoming calls). This allows you to save on telephony without overpaying for internal calls.

Setting up and connecting a VoIP adapter

Connecting a VoIP adapter is not difficult even for those users who do not have the skills to work with telephony and similar equipment. The device is connected to a landline telephone via FXS. The LAN cable is connected to the router. For the system to operate, stable Internet access is required. After connecting the cords, you need to install software that will allow you to configure the operation of the adapter. Management occurs via a web interface. The necessary software is supplied with the adapter (it can also be downloaded separately from the manufacturer’s website).

Basic features that the VoIP adapter provides:

Creation of audio and video conferences;
Recording conversations (you can listen to them via the web interface);
Analysis of call statistics from each telephone device;
Formation of a voice menu + reading (IVR);
Speed dialing and blocking numbers;
Waiting, call forwarding.

Additional features vary by device model. All adapters support voice transmission in G.711, G.729A/AB and G.722 codecs. Due to this, high-quality signal transmission is achieved and sound is transmitted in HD without interference. Support for several protocols makes the adapter functionally indistinguishable from IP phones.

Pros and cons of using

VoIP and SIP adapters have the following advantages:

No need to buy new IP phones (adapters allow you to connect several landline phones, depending on the model);
Support for full-fledged business functions for corporate communications (voice menu, call recording, etc.);
Significant budget savings on communications (since the signal is transmitted not through the telephone network, but via the Internet);
Possibility of forming a corporate connection from anywhere on the planet.

Adapters also allow you to call mobile phones without overpayment. This is relevant for offices that periodically make calls to employees and clients. Additionally, users can combine their branches into a single network, even if the adapters are installed remotely.
However, VoIP and SIP adapters also have disadvantages. The main disadvantage is the relatively low degree of protection of the transmitted signal. Otherwise, we can talk about the advisability of installing the adapter in offices and other commercial premises for small and medium-sized businesses.

Available in two modifications SIP-CDA1 and SIP-CDA2, differing in the type of use (handset / entrance).

Purpose and operating principle:

The SIP coordinate intercom adapter is designed to integrate SIP telephony based on SIP servers, IP PBX and/or SIP subscriber equipment into standard coordinate intercoms Visit, Eltis, Tsifral, Metakom. The operating logic of the switch for a specific intercom is selected in the settings of the WEB interface of the adapter. Intends use as a SIP intercom with the function of opening a door (relay control) from any telephone device (device, interface) or SIP client (program installed in a mobile phone, personal computer, tablet, TV, etc.) together with analog handsets , switches. Subscribers who do not need to connect the intercom to the telephone network and/or do not want to give up the handset can continue to use the intercom as usual. Connection interface - Ethernet, connection via Wi-Fi access point is possible. To connect the SIP adapter to the server, no port routing is required; all SIP-CDA subscribers can contact the server from anywhere on the global network. Depending on the settings of a particular subscriber, it assumes different logic of calls, either only to SIP or only to the handset, and simultaneously or completely blocking the subscriber. SIP-CDA1 is connected in subscriber line mode to the line and handset inside the apartment. SIP-CDA2 in switch mode is connected to the inputs of the entrance system switches and is designed to serve one entrance. When dialing a subscriber's number on the calling panel, the call is sent according to the entry in the subscriber database to the handset and the specified phone number; a call can only be made to the handset or telephone, as well as sequentially if there is no answer. It is possible to completely disconnect a subscriber, which is convenient for remotely blocking debtors. If there is no entry in the SIP subscriber database, the call is routed to the handset. When you pick up the handset, the call to the phone ends. When answering the phone, it is possible to talk and open the door and, if the subscriber is allowed (for example, a concierge), turn on any of the two loads (for example, lighting). There are two inputs for sensors, upon activation of which a telephone call can be received with single or double beeps, respectively, to inform about the operation. When there is an incoming call to the adapter, if the subscriber is allowed to do so, it is possible to control loads, one of which can be connected to the exit button of the main intercom (on the entrance door, not the handset) to randomly open the door, either by dialing a control command or automatically, if this is determined by the subscriber settings. Thus, in relation to the SIP-CDA2 adapter, when approaching the entrance, you can open the door by calling from a registered phone. In addition, it is possible to implement a function in which the door (barrier, gate) will be open while a call is in progress (there is an established connection), upon completion of which the system will give a command to close the passage.

The easiest way to organize receiving calls from a coordinated intercom on any telephone device, tablet, PC, etc. This is a SIP account service from a telecom operator. For example, a virtual PBX from the oldest IP telephony operators SIPNET and Zadarma, or the MultiFon service from the cellular operator Megafon. There are many similar offers on the market. It works extremely simply. The telecom operator allocates a SIP account to the subscriber, with which the SIP-CDA adapter connects via the Internet. Thus, a call from the intercom can be directed both to the Internet and to the public telephone network. Accordingly, you can accept a call either on any classic telephone device (landline or cellular), or on any Android device, using any SIP client, for example, Emotion from the same Megafon. In addition, no one is stopping you from installing your own IP PBX (for example, the Komendant IP PBX is provided free of charge) on any computer on the network, and ultimately get a completely controlled and independent situation. Also, it should be noted that for a small number of subscribers, virtual PBX services from some operators can be either symbolic or completely free, which not only radically reduces the cost of communication services, but also frees them from the need to maintain their own administrative and technical staff.

Synchronization with (internal or external) video stream to enable video calls:
Making a video call is implemented by specifying in the settings the request string of the relayed video stream (H.264) from the IP camera to the SIP client. RTSP/RTP control protocol. The ability to view video also depends on the SIP client. As a rule, only low-resolution video calls (CIF) work stably; accordingly, the IP camera must support low-resolution video streams starting from 320*240. The maximum size of an RTP H264 packet should not exceed 1500 bytes; more, as a rule, is not supported by sip clients. Supported resolutions: 704x576 (D1) from 1 to 25 frames per second; 352x288 (CIF) 1 to 25 fps. Camera example: - Tantos TSi-Pe1F. Before purchasing an adapter, you can remotely test your video stream on our equipment.

Remote control via the Internet:
The SIP-CDA adapter is controlled via the WEB interface. No DHCP. If remote management of SIP-CDA is required in the absence of a dedicated IP address and/or the possibility of organizing appropriate routing, then one of the medium-budget options is to use simple routers with VPN support. For example, Mikrotik hap lite rb941-2nd or Mikrotik hap lite rb941-2nd-tc, as well as the like, there are many more advanced and very budget offers on the market, starting at $15 per router. In this case, SIP-CDA adapters are connected to the Internet through similar routers, through which the adapters are connected to a remote server (for example, to a computer in the office of an intercom service company), through which their centralized administration can be implemented.

Functions [adjustment and/or development of individual algorithms is possible]:

1. Two operating modes: subscriber line (apartment) and switchboard (entrance).
2. Support for intercoms Visit, Eltis, Digital, Metacom.
3. Flexible configuration of line and switch parameters.
4. Subscriber call settings: no call (complete subscriber blocking), handset only, SIP only, SIP - handset on no answer, handset - SIP on no answer, SIP and handset at the same time. Non-response time 1-255sec.
5. Possibility of assigning automatic opening to the subscriber on non-response for 1-255 seconds.
6. Possibility of allowing the subscriber to control loads during an incoming call, incl. exit button (opening the door from the phone) by dialing the opening code or automatically.
7. 2 inputs for sensors for a telephone call with a sound alert if they are triggered.
8. Flexible numbering plan for opening codes (default 55) and load control.
9. Load operating modes:
- switch on for 1 - 254 sec.
- on/off
- synchronization with a call (for example, to control lighting or rotate a video camera).
10. Call when sensors are triggered, selecting the called number separately for each sensor. It is possible to connect alarm sensors for audio notification by telephone.
11. Protocol support
- Supports management via SIP INFO or RFC2833 RTP EVENT.
- Select transport protocol for SIP: UDP only
- The adapter is configured via the WEB interface.
...and that's not all, new features are coming very soon

Specifications:

Supply voltage 12V / Current consumption 0.2A
Ethernet connection interface 10BASE-T
Idle traffic ~340 bytes/min, ~15 MB/month
Audio: G.711 (a-law), sound quality: 8 kHz 8 bit
Number of loads controlled (open collector): 2
Controlled load parameters: switched e.g. 60V, current 0.5A
Number of sensor inputs: 2
Number of subscribers: 500
Recommended SIP clients: Linphone, Zoiper, MicroSIP, CSipSimple

Connecting the SIP-CDA coordinate intercom adapter:

1. SIP-CDA1: connect the line to the H-, H+ contacts and the handset to the L-, L+ contacts, observing the polarity. SIP-CDA2: connect the switch control contacts H-, H+, L-, L+, GND, D0, D1, D2, following the connection diagram depending on the brand of the intercom.

2. Connect controlled devices (relay coils) to the contacts of external devices and the “+” power supply of external devices. If necessary, connect an external relay for controlling lighting or other devices. When using external relays, install an FR-207 diode or a similar one in parallel with the relay winding with the cathode (white stripe) to the “+” power supply; failure to observe the polarity can lead to failure of the power supply. The absence of a diode makes the relay winding a source of powerful electromagnetic interference, which can lead to malfunctions of electronic equipment in the room. To use the opening function by calling from a telephone, you must connect one of the control contacts to the contact of the intercom exit button.

3. Connect motion sensors, passage sensors, etc. (if provided) to the sensor inputs and common wire.

4. Connect the power supply to contacts +12 and common, strictly observing the polarity.

5. Connect the Ethernet network to the RJ-45 connector.

6. Connect the power supply to the electrical network.

7. Go to software settings.

Software settings:

The software settings of the SIP-CDA adapter are standard and fully correspond to the classic settings of VOIP (SIP) equipment and modern intercom systems.

1. Press and hold for more than 1 second. network settings reset button. The default IP address will be 192.168.0.127.

2. Enter the IP address 192.168.0.127 into the browser address bar and wait for a response from the adapter management web interface. The default login is admin, password is masterkey

3. Configure the adapter settings.

Special instructions for some intercom models and/or additional equipment:

Visit BUD-420M
Intercom type (Equipment settings ->): Visit BUD302
SIP-CDA1 (Adapter settings ->) lower line level: 1300, upper line level: 3500, conversation load: 2
SIP-CDA2 (Adapter settings ->) lower line level: 2100, upper line level: 3700, conversation load: 1

For Metakom intercoms

When using SIP-CDA2 without a switch or a switch with a voltage on the Data contact of 10 - 12V, you must connect a resistor in the range from 1 to 10KOhm between the Data and +12V contacts of the calling panel; for a switch with a line voltage of 4 - 5V, a resistor is not required.

IP telephony is known throughout the world as a means of communication with extremely low tariffs. At the same time, neither traditional wired telephony nor cellular communications can compete with it. To ensure more convenient communication with the world via IP telephony, subscribers are recommended to purchase a SIP adapter. With its help, they will be able to talk with other people without a computer, which provides special convenience for telephone conversations.

Most subscribers use traditional computers with headsets connected to them for IP telephony conversations. It turns out that when the computer is turned off, you won’t be able to call anywhere. Also, we can note the following inconveniences:

Possible computer occupancy;

The need to use a headset;

Inability to accept an incoming call when the computer is turned off.

Confidentiality is also violated - you wouldn’t talk about purely personal topics with a headset on your head at the moment when someone else is working on the same computer at the same time? How to ensure the convenience of conversations via IP telephony? In this case, you should buy a VOIP adapter that connects to the Internet.

What is a SIP adapter (or VOIP adapter) and how does it work? The adapter is a small box with LED indicators that connects to the Internet via a router or any other device used to connect to the network. The most common telephone used in traditional telephony is connected to the adapter itself.

In order for the SIP adapter to work, it must be configured to communicate with your SIP server or with the server of the selected telecom operator. Settings and parameters are entered via the web interface. After completing the settings, connect the telephone to the adapter and try to make calls.

Please note that a computer is needed here only for the initial setup - later the SIP adapter works in completely autonomous mode, without requiring any intervention.

The simplest VOIP telephone adapter is equipped with two ports - the WAN port is used to connect to the Internet, and the FXS port is designed to connect a regular telephone set and emulates the operation of a telephone exchange. Connection to a computer to configure the device is carried out using the WAN port. There is also a connector on board for connecting a power source. Some models are equipped with additional ports for connecting another phone or for connecting to a computer.

Additional features of SIP adapters:

Noise reduction is a great option if the phone is in a noisy place;
The ability to connect to two servers/providers - useful when optimizing communication costs;
Wi-Fi connection will save your apartment from unnecessary wires;
Ability to work with two or more accounts – relevant when using separate access to communication services;
Number identification is a convenient option for those who use IP telephony for incoming calls;
Conference calling – the ability to organize communication with several subscribers at once;
Holding and waiting for a call – the ability to alternately communicate with several subscribers;
Speakerphone – you can talk even without a telephone;
Support for the Skype protocol – low-cost IP telephony and Skype phone “in one package”.

Many other features have also been implemented that significantly expand the functionality and make communication more convenient. The availability of certain functions can be found in the passport for the device.

Popular SIP adapter models

When planning to buy a VOIP adapter, you should familiarize yourself with the most popular models:

Cisco SPA112;
Cisco SPA122;
Grandstream HT701.

The Cisco SPA112 SIP adapter is the simplest model developed by a world-famous brand. The adapter is equipped with one port for connecting to the Internet and two ports for connecting telephones. There are no call management options here - no conference calls, no hold or call waiting. But there is a voice activity recognition system that saves traffic.

The next model, Cisco SPA122, is similar to the previous one. It can connect to several servers, has the functions of a voice gateway and router, and is endowed with the generation of comfortable noise, replacing silent pauses in a conversation. Also echo cancellation function implemented. Number of FXS ports for connecting telephone sets – 2 pcs. The Grandstream HT701 SIP adapter is equipped with only one port for connecting a telephone.

But there are additional call management functions - conference calls, call hold and waiting, caller ID. The model is extremely simple, but it performs its functions perfectly.

Which VOIP adapter to choose

When buying a VOIP telephone adapter, you should first decide on the functionality. If you need a simple adapter for periodic conversations, choose the simplest model. If you want to use not only IP telephony, but also Skype, then we are looking for a model that supports the Skype protocol. As for the number of handsets, a SIP adapter with one FXS port is quite sufficient for home use.

I like it I don't like it

IP telephony is characterized by low cost and at the same time unlimited coverage area. The only problem is that connecting it requires special technical means. The VoIP adapter is considered perhaps the most popular unit for providing communication via the Internet. Let's find out what it is, how to set it up, and which models are trustworthy.

Let's start with the fact that VoIP adapter and SIP adapter are two variants of the name of the same block. The fact is that the SIP protocol is considered a newer version within the VoIP protocol. If VoIP is a general system, then SIP is designed specifically for IP telephony.

Features of use

There is an opinion among ordinary people that a computer is best suited for setting up and operating a telephone line on the Internet. Indeed, a computer, laptop or a good tablet can provide communication, but this approach is inconvenient.

The equipment takes a long time to load when turned on.
If someone is working at the keyboard, then you will either have to move him or stand next to him and talk about his own things, which is extremely inconvenient.
The equipment must be equipped with speakers and a microphone or a headset is required.
If the equipment is turned off, then you can forget about communication.

In general terms, a telephone adapter is a small box that, on one side, is connected to an Internet line via a modem or router, and on the other, a regular analog telephone is connected to it. Thus, through an inexpensive city telephone or several telephones, you can talk over a multi-channel IP number.

For the SIP box to work, it must be configured to the parameters of the selected IP provider. This is where a computer is needed, the required settings are set through the web interface, after which the adapter will work autonomously, without the participation of a computer.

Basic features provided

Despite its modest size and reasonable cost, the software of such equipment provides ample opportunities. For personal use or the needs of a small office, these options are more than enough.

Organization of conferences in audio and video format.
Recording and listening to telephone conversations in automatic and manual modes.
Accounting of statistics of incoming and outgoing calls for each channel and phone.
The device has a voice menu, which also allows you to organize readings.
Black list of numbers and speed dial programming.
Standby mode with answering machine, plus forwarding.
Noise filtering mode is relevant for shops and communication in production.
Simultaneous work with two providers.
Built-in Wi-Fi “umbrella”, which allows you to do without internal cable lines.
Caller ID (Caller ID) for incoming calls.
Speakerphone output.

There are adapter models that allow you to work with Skype and IP providers simultaneously, but this is an additional function that is not built into every device.

Pros and cons of using

The high popularity of such equipment is due to a number of serious advantages; most users note the following advantages:

The price of one telephone set adapted for IP communication is equal to the cost of an average adapter, but up to 10 inexpensive analog devices can be connected to a small box, thereby providing communications to all departments of a small office.
The equipment has all the necessary functions for organizing full-fledged corporate communications.
The average PC user is quite capable of setting up the adapter with his own hands; most models have an intuitive interface.
Once configured, the adapter does not require computer support; the equipment operates autonomously.

This equipment is not perfect; it also has several noticeable shortcomings.

Unlike analog phones, all IP equipment requires power supply and Internet access; in other words, no light, no connection.
Cheap models cannot provide really high-quality communication for more than 1-2 telephones.
If the number of connection points in the office increases, you will have to buy new devices; even the most “dressy” adapter is designed for a maximum of 10 phones.

In order to increase sales, many marketers call SIP adapters gateways - this is incorrect. SIP or VoIP gateways have similar functions, but the power and quality of the software is much higher, which is why they cost several times more. For those who are planning expansion or are concerned about the stability of the connection, it is better to take a SIP gateway.

To set up a telephone adapter with your own hands, you will need the adapter itself, a router or switch, an analog telephone with a touch-tone dialing function, and a computer. As an example, we took the GrandStream HandyTone-802 model. First, everything is connected into a single system.

The computer is connected via a LAN connector.
Router, or switch, through the WAN connector.
There is a separate connector for the power supply.
Two or more connectors are allocated for analog phones.

The default IP of the adapter is 192.168.2.1. is stated in the documents, but if the IP is unknown, then after connecting you need to dial the combination “**#101 Call” from your phone, you will be told the number (in English). Next we need to change the address of the network adapter on the computer. The sequence of actions looks something like this:

Right-click on “Local Area Connection” and select properties.
Select “Internet Protocol Version 4” and click properties.
In the window that opens, select “Use the following IP address.” In the IP address field write 192.168.2.2. In the subnet mask field write 255.255.255.0. then click OK and close.
Now open the browser and enter 192.168.2.1 in the address bar.
A login form will open at the address. Instead of the default password, write “admin” and log in.
Go to the “FXS PORT1” tab.
In the Accoynt Active field we set Yes.
In the Primary SIP server field, enter the address of the communication provider.
In the Prefer Primary SIP server field, check the Yes box.
In the Outbound Proxy field, enter the city code, which is found through the SIP provider's support service.
In the SIP transport column, check the UDP box.
In the SIP User ID column, you need to enter data from your SIP provider’s personal account; the code is located in the “Equipment Setup” section (in the “Line Port” field).
In the Authenticate ID field, enter the login from the equipment settings item in your personal account.
In the Authenticate Password field, enter the password from the equipment setup item in your personal account.
In the Name field, enter the account name.
Now we go down and find the Preferred DTMF method column, there, in the drop-down menu, in the Priority1 value we select RFC2833.
Go to the very bottom of the page and click Update.
Then the window will close and you will need to click Reboot. The reboot takes 30-40 seconds. After that, the background1 indicator on the adapter will light up and it will be ready for use.

Popular SIP adapter models

There are more than enough offers on the market now, but there are several popular models that are always popular.

GrandStream HandyTone-802– we looked at its settings in the previous chapter. The device has the following functions:

conference call;
voice activity recognition;
supports two telephones;
noise suppression;
support for multiple IP servers
queuing and holding a call;
Dimensions 100x100x30 mm, weight 114 g.

Cisco SB SPA122-XU– the model is produced by one of the world's leading brands. The device is unpretentious in operation and is highly reliable. As for the parameters, they are similar to the previous model.

Cisco SPA112– is considered one of the simplest, budget models. There is no conference calling, call holding, queuing or call management, but traffic savings are provided. In general, a box for home use with slow Internet.

Which VoIP adapter to choose

You need to start from practical expediency. For personal use, conference calling and various types of call management are often not needed, but many people want to connect Skype; by the way, the integration function with Skype can increase the price of the device by a third.

When it comes to business, it is advisable to buy equipment with as many telephone connectors as possible; the maximum for adapters is 8-10 points. The functionality and software of such models are quite decent, but they are somewhat more expensive, plus you need to choose proven brands like Cisco or GrandStream.

Telephone adapters are considered an excellent solution to communication problems for homes and small businesses. They are made for those who need to connect an inexpensive phone quickly and without any hassles.

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