Our virtual telephone system already offers small and medium-sized companies a number of advantages: It saves installation costs and space, is inexpensive to operate and breaks less often than conventional telephone systems. With our new, free app, telephony is now even more mobile, because not only stationary desktop or DECT telephones can be connected to the telephone system in the cloud from anywhere, but also any smartphone with an Android or iOS operating system.
Modern telephony that lives up to the spirit of the times
After you have installed our app on your smartphone, you can use the app to make phone calls via the telephone system. When you call someone from the app, the person you’re calling will see your landline office number. This way you avoid using your private mobile phone number for business calls while on the move. In addition, telephone calls via the telephone system are often cheaper than via your mobile phone provider – especially abroad.
If you are called from a landline on your office number, your smartphone rings and you can answer the call with it. This saves you the cost of transferring calls from your office number to your mobile phone.
The app on your smartphone can also replace your employee’s desk phone in the office. This allows companies to dispense with the purchase of expensive end devices. Desk phones and apps can also be used in parallel. Telephony with the app works wherever the user is connected to the Internet via wifi, 3G or LTE. Good reception is very important. If the data from your mobile phone to our telephone system is transported immediately and loss-free through the Internet, you are making calls with excellent voice quality.
How VoIP telephony works on your smartphone
The best features are worth nothing if they are complicated to implement and unintuitive to use. That’s why the installation and setup of the app is just as easy as its use. To securely log the app on to the PBX, you don’t need to enter complicated access data. Instead, the app conveniently configures itself almost automatically using a QR code.
In order to guarantee the confidentiality of your calls even in public wifis, we encrypt your calls with SIPS/SRTP. This makes telephony with the app a fully-fledged alternative to normal mobile telephony via your mobile phone provider.
A look under the hood
We have been working on the new app for quite some time and had to learn that telephony from an app on the smartphone is technically challenging to implement. When we looked at existing apps for the first time over two years ago, it quickly became clear that we had to avoid a few pitfalls.
Our usual VoIP telephones connect to our servers after the start. The phones keep this connection open to get notified on incoming calls. Theoretically, we could let the app work in the same way. But then the app would have to be active in the background all the time and constantly maintain a connection to our servers in order to ring when a call comes in. That eats battery. A lot of battery!
The solution are push notifications. With the help of push notifications, the app on the smartphone can be inactive when you are not making a phone call. If a call comes in, we send a push notification to the smartphone and the app is only “woken up” at this moment. This has the small disadvantage that the mobile phone sometimes only starts ringing one or two seconds later when a call is received for the user. But the app doesn’t suck the battery out, even though the user doesn’t make any phone calls. All things considered, this is a very good compromise.
Telephony naturally reacts very sensitively to packet loss or latencies during data transmission in the network. If packet loss occurs when you access a website on the Internet, you usually don’t notice it because your browser simply repeats the request to the server and the website is then displayed to you with minimal delay. If, on the other hand, a packet is lost during a phone call, the other party will hear this immediately and rate the voice quality as poor. Because packet loss is more common in many wifis, we recommend connecting VoIP phones to the Internet via cable instead of wifi. But a smartphone does not have a network interface (and that’s a good thing). Instead, the smartphone transmits its data – depending on availability – via wifi or in the mobile network via 3G or LTE. A stable wireless connection is therefore a prerequisite for telephony via app on the mobile phone.
However, because packet losses in a wireless network can never be completely avoided, we have helped to ensure the best possible telephony experience even under these circumstances: Our app uses the modern Opus codec. This codec helps to correct errors in voice transmission due to packet loss and latency.
With our new app we have succeeded in bringing the once spatially bound, dusty telephone system even further out of the cellar and into the 21st century. Telephony as a service from the Internet is now completely mobile, location-independent and tap-proof at the same time.