What is a softphone?

A phone that is only software

The word softphone combines software and phone. Instead of buying a device, you install software — and it does everything an IP phone does: it registers with the PBX, rings, shows who is calling and lets you transfer a call. The computer screen is the phone's screen, and the headset is the handset.

There are two main forms: computer software (Windows or Mac) and a mobile app (Android or iPhone). The principle is the same — both connect to the same extension over the internet. These are not general calling apps that talk only to other users of the same app; a softphone connects to the PBX and dials any phone.

How it works behind the scenes

1. You install the software and enter the extension details: server address, username and password.
2. The software registers with the PBX using the SIP protocol — exactly like a desk phone.
3. When a call arrives, the PBX sends it to the software, and it rings on the computer.
4. Your voice is picked up by the microphone, compressed with a codec and sent in small packets over the internet.

A mobile app has an additional step: smartphones "put to sleep" background apps to save battery. That is why many apps use push notifications — the server "wakes" the app when a call arrives. If notifications are blocked or battery saver is aggressive, the call may not ring. This is the most common reason for the complaint "the app doesn't ring."

When it fits

• Working from home — the same extension as at the office, with the same queue and the same recordings.
• Call center agents who work at a computer anyway and open a customer record during the call.
• Travel — a manager abroad answers his extension from the hotel over Wi-Fi, and calls customers as if he were at the office.
• Temporary volunteers — at a fundraising evening, each volunteer can get an extension in the software or the app, and it can be removed the next day.
• Employees without a fixed desk — who move between workstations and want their extension everywhere.

What matters for call quality

A softphone is only as good as its weakest link. Four things determine the quality:

• Headset — a microphone close to the mouth with noise filtering. A laptop's built-in speaker and microphone create echo and noise.
• Internet connection — a call needs little bandwidth, but a stable connection. A cable to the router is better than Wi-Fi, especially if the home is full of devices.
• The computer — a computer loaded with dozens of tabs and heavy programs can cause choppy audio.
• The network — on a slow VPN or a crowded public network (hotel, café) there may be delays (latency and jitter).

Advantages and Limitations

The kosher phone limitation is especially important in our community. Someone without data access can't use an app — so for them there is a SIM extension, which works without internet at all.

Softphone or desk phone

This question comes up in every office that moves to the cloud, and the answer depends on the work, not on the technology. For an employee who handles dozens of calls a day, physical keys and indicator lights are a matter of speed — a desk phone will win. For an employee who answers calls while typing at the computer anyway, software with a headset is more comfortable: there is no handset wedged between shoulder and ear, and the customer's number is already on the screen.

There is also a reliability consideration. An IP phone turns on in the morning and works; you don't need to remember to open it, and it doesn't update in the middle of the day. A softphone depends on the computer being on, the software being open and the speakers not being muted. That's why many call centers choose a middle path: an extension that rings both on the desk phone and in the software, and each agent answers wherever it's convenient.

And for someone who works from home only sometimes, a softphone is the cheapest and simplest way: there's no need to buy a second device, and the extension simply "travels" with the laptop.

Correct installation in five minutes

1. Install and enter the extension details exactly as you received them — with no extra spaces in the password.
2. Allow microphone access when the computer or mobile asks. Without it, the caller won't hear you.
3. Choose the headset in the software as the audio device, not the computer's speakers.
4. Set the software to start with the computer, and on a mobile — allow it to run in the background and receive notifications.
5. Make a test call — incoming and outgoing, and check that both sides hear well.

Common mistakes

• Forgetting to open the software in the morning — set it to start automatically with the computer.
• Answering on the mobile speaker in an open space — the caller hears the whole office.
• Keeping the same extension on two computers that stay on — the call will ring on a computer that nobody is sitting next to. It's not harmful, but it's confusing.
• Keeping the password in a visible place — anyone who has the extension details can dial at your expense (toll fraud).

An end-to-end example: a fundraising evening with twenty volunteers

A nonprofit organizes a telephone fundraising evening. Eight volunteers sit in the call center, and another twelve answer from home. They all need to answer the same queue, and the next morning nothing is needed from them. Here is how it goes with a softphone:

1. Two days before — open twenty temporary extensions in the range 700–719, add all of them to the "Donations" queue, and set up a callback for anyone who waited and hung up.
2. One day before — each volunteer receives a message with his extension details and an installation link. He is asked to make one test call to the coordinator's extension.
3. One hour before — the coordinator opens the Queues screen and sees which of the twenty are registered and connected. Three are not — he calls them. Two forgot to turn on the software, and one didn't allow the microphone.
4. During the evening — the calls are divided between the call center and the homes without the donor knowing. A volunteer who goes on a break pauses himself in the queue; the coordinator sees who is talking, who is available and how many are waiting.
5. The next day — delete the twenty extensions. No one can dial at the nonprofit's expense anymore, and there's no equipment to return.

What made the difference: the test call the day before. Without this "plumbing" check, three extensions would have failed at peak time instead of during preparation.

When it doesn't work: symptom, cause, fix

A time-saving rule: if the mobile app doesn't ring but does ring when it is open on the screen — it is almost always a battery or notifications problem, not a PBX problem.

Softphone and the rest of the system

Because the softphone sits on the computer, it meets the other tools the employee works in — and that's where most of its value lies:

• Queue — an agent joins a queue, pauses himself and leaves it from the control panel; in the software he sees that the call came from the queue and not directly, and knows to answer "Hello, you've reached customer service."
• Customer system — in many systems you can dial by clicking a number in the customer record, and the call goes out from the extension (CRM integration). This saves typing and mistakes.
• Extension keys — many programs show a list of colleagues with an available/busy indicator, the equivalent of the BLF lights on a phone.
• Recording and call log — these are set for the extension, not the device. A call answered in the software is recorded and appears in the log exactly like a call on the desk phone.
• Conference rooms — from the software it is especially convenient to join a conference room: the number and the code are already on the screen.

And something about history: calling programs for computers appeared as early as the mid-1990s, but for years they were "computer to computer" only. The softphone in today's sense — software that registers with a PBX using the SIP protocol and dials any phone — spread in the decade that followed, together with cloud PBXs.