General Telephony

With Robocalls On the Rise, FCC Issues Ultimatum to Telecoms

RobocallsIf you have received an automated call to your home phone or smartphone recently, you’re not alone. The Federal Communications Commission (FCC) estimates that, if nothing is done to combat the problem, robocalls could represent nearly half of all calls in 2019.

The The Washington Post reports that this increase in robocalls is part of a multi-year trend where spam has jumped from 3.7 percent of total calls in 2017 to 29 percent this year. This dramatic increase has finally forced the FCC into action. An FCC press release this past week says the federal organization “will do everything we can to catch and stop spammers” and that it’s urging VoIP providers to “implement tools to speed the traceback process” to catch spammers in the act.

Furthermore, the FCC issued letters to 14 prominent telecommunications companies demanding that they implement the SHAKEN/STIR method of call protection. The Commission’s rhetoric includes the promise that it will “take action” if the telecoms do not fall in line.


The Signature-based Handling of Asserted Information Using toKENs (SHAKEN) specification and Secure Telephone Identity Revisited (STIR) protocol provide methods for caller identification. They appear to be the best chance the telecommunications industry has in defending the public against robocalls.

You can think of these protocols as the equivalent to websites that use the https:// communications protocol. In short, https:// sites differ from ordinary http:// sites because they use a method of encryption called Transport Layer Security (TLS). TLS makes sure that the information you send from your computer to a website is unable to be read by any entity except you and the website you want to reach.

TLS is essential for online banking, purchases on e-commerce sites, and sensitive communications between individuals. In addition to encryption, TLS also identifies the parties involved (in this example, you and the website) so bad actors can’t get in the middle and intercept your communications.

SHAKEN and STIR offer similar protections. SHAKEN defines the framework within which STIR can function. They work together in your phone system to identify callers and make sure that calls on a SIP session originate from an approved location.

How Does This Affect VirtualPBX?

The robocall spam you receive happens from within networks that use IP-based calling mechanisms. Spammers use the same type of technology that much of the telecom industry, including VirtualPBX with its Business Phone Plans, uses to process legitimate calls.

Spammers can enter the market for an extraordinarily low cost. They can also rely on the fact that the system isn’t inherently built to stop them. There’s no mechanism in place to establish secure, verified SIP calling sessions in a way that combats spam.

SHAKEN/STIR can effectively shake up (sorry) the situation by creating a mechanism where information stored in each calls verifies the legitimacy of the caller. It will also work with non-SIP parts of calls to further validate call origination along its path.

You can read more about how the PSTN handles VoIP calls in a feature on our blog. For this robocall issue, understand that there are parts of the public phone system that use the internet to manage calls. Not all of the information used in an IP-based call is necessarily used in an analog call, but SHAKEN/STIR should have the ability to authenticate data through the entire path, regardless of the underlying platform.

Protecting the Consumer

VirtualPBX and other hosted phone service providers use carriers – including the ones the FCC addressed in its letters – to move calls between their endpoints. The adoption of SHAKEN/STIR methods across the board will be good both for individual consumers and our business customers.

When we hand off calls to carriers, we can be sure that their internal processes verify the authenticity of those calls. This situation will hurt spammers’ ability to flood our customers’ phones with robocalls, and it will create a more secure network for calling overall.

We’re excited to see what the telecom industry will do with these new spam-fighting processes. And we certainly hope that, in the coming months, the number of robocalls inundating the public will shrink and disappear.

How the PSTN Interacts With Your VoIP Calls

PSTN SwitchboardIf you take a look at our What is VoIP? guide, you’ll read about how the Public Switched Telephone Network (PSTN) comprises a host of analog and digital systems like cellular networks, undersea fiber optic cables, and copper telephone lines that allow people across the globe to complete voice calls.

The PSTN plays a primary role in many of the calls you make during your voice over IP (VoIP) calls, too. In fact, if your calls reach a residence or business with a landline – which a U.S. Center for Disease Control study showed that about 45 percent of households had in 2016 – you will use the PSTN to make those connections.

Let’s take a look at how your outbound business calls to customers’ landlines and cell phones would use the PSTN to transmit calling information.

About Switching Centers, Quickly

Before we get started, it’s important to know that the PSTN uses switches to transmit calling information in its network of hardware.

Calls in the PSTN often first make their way to a central office. This switching center is located close to where a call originated, such as a home phone subscriber’s residence.

Then those calls are commonly sent from the central office to a gateway — also known as a tandem office. The gateway switch is typically connected to multiple phone carriers’ interconnects – such as AT&T or CenturyLink – so carriers can route calls into each other’s local networks.

You may remember the switchboards that required individuals to manually connect incoming calls to their destinations, as is shown in the image above. Today, we have replaced those jobs with digital switches, which are just electronic devices that could fit on your desk.

The digital switches mentioned previously — the central office and gateway — make it possible for switching in the PSTN to take place not necessarily in entire buildings but in rooms that contain multiple pieces of automated telephony equipment.

The word “gateway” can refer both to a centrally-located office and the piece of telephony equipment that processes calling signals. Interconnects are a type of gateway hardware.

Business VoIP Call to Home Landline

With that information about switching centers in mind, imagine this first situation as one where your business is calling a customer’s home landline. You will call outbound from your VoIP desk phone that’s connected to a hosted VoIP service like our Dash Business Phone System.

First, the phone number you dial on your VoIP phone will make its way through the internet to VirtualPBX, your hosted phone system provider. The provider will then hand that information to a carrier, which will have to determine where to further move the call. At this point, your calling information will be in a gateway.

The gateway will move your call through one or more other gateways before it reaches a location that’s close to the customer.

When the final gateway is reached, if necessary, the carrier who moved your call to that location will hand the call through its own interconnect to another carrier’s interconnect – the carrier which owns the service the customer subscribes to. (This handoff may not be appropriate if the customer subscribes to the same carrier that moved the call to the ultimate gateway office in the first place.)

That final carrier handoff will take place at the gateway switch. Following that handoff, the gateway will then move your call to a central office.

Finally, the central office will reach the customer by ringing their home phone.

This process will work in reverse when the customer answers their phone and information is sent back through the system to you, the caller.

Business VoIP Call to Mobile Phone

What happens when you want to call a customer’s smartphone from your VoIP desk phone? Now that you understand the process of reaching a home phone, the change to a mobile phone is relatively easy.

All those previous steps are similar with the exception of one. When your outbound call finally reaches the ultimate gateway, it won’t need to seek out a central office.

Instead, the gateway will send the call digitally through the cellular network to a cell tower that rings the customer’s phone.

VoIP-to-VoIP Calls

In some cases, your calls might avoid much of the PSTN.

Consider that you, a VirtualPBX subscriber, want to call a customer that uses Vonage. It’s possible that your outbound call will reach a VirtualPBX host, connect to a VirtualPBX carrier, be routed through the internet, connect to a Vonage carrier, and finally reach the Vonage user.

That call would never touch a copper wire or a cell tower. You would have sidestepped the PSTN because you used the internet, and not traditional telephony infrastructure, to move calling information from one VoIP phone to the other.

Carriers move their information in different ways, so it isn’t always accurate to say that a VoIP-to-VoIP call would have bypassed the PSTN. However, it is possible, and with gains in VoIP use at businesses and homes, it may become more likely.

What is the PSTN? The Takeaway

What you should take away from this short lesson is that the remnants of the PSTN past are still necessary for modern communications to function. If you didn’t have central offices that transmit digital data or copper wires that carry analog signals, the communications system as we know it would break down quickly.

Keep these ideas in mind the next time you dial a customer or accept an incoming call. It’s a jungle of buildings, switching, and lines, but it all functions together to make your seemingly simple phone calls possible.

Hungry for more? Keep reading to learn about packet switching, codecs, and the entire VoIP landscape.

Which Audio Codec Fits Your Business Best?

Conference Phone - CodecNo matter which Dash Business Phone Plan you use, any IP phone linked to that plan must utilize a codec to send and receive digital audio information through your local network and the internet.

All phones you order through the VirtualPBX Online Store come preconfigured, and each specific model will choose a default codec to use. Should your situation call for it, however, you can select other options, including the popular codecs G.711, G.722, and G.726.

There are a number of reasons why you would want to use any specific codec on your business phones. Let’s take a look at G.711, G.722, and G.726 as examples to illuminate those reasons.

Three Popular Codecs


G.711 has gained widespread support since its release in the 1970s. This codec is part of a narrowband set of codecs because it uses audio frequencies in a range of 300 to 3400 Hz.

Documentation from Cisco shows that G.711 has a Mean Opinion Score (MOS) of 4.1 which, within that rating scale of 1 to 5, represents an audio quality considered good.

Many phones support this codec because of its high call quality and reasonable bandwidth requirement of about 87 kbps.


G.722 improves on G.711 in at least one respect. It operates in the wideband range of 50 to 7000 Hz, which allows it to offer better clarity and more natural sounding audio to the receiver.

G.722 achieves this higher audio quality while maintaining a 4.1 MOS and demanding only 87 kbps in bandwidth per call.


G.726 works in the narrowband range. It uses compression and a lower bitrate to decrease its bandwidth demand on a user’s phone system. This codec can use a bitrate of 16, 24, 32, or 40 kbits — lower than the common 64 kbits of G.711 and G.722.

When using a 24 kbps bitrate, it only requires 47 kbps of bandwidth per call, which is nearly half of G.722 and G.711. This comes at a price however, because its MOS drops to 3.8, which is a significant drop from the other codecs listed in this article.

Which Should You Choose?

When looking at these codecs, three aspects of their operation stand out. You will want to consider their bandwidth requirements, call quality, and popularity when choosing one for your own business.

  • Bandwidth: Your internet connection will need to be robust enough to support the combined bandwidth of the phones you want to use. For example, if you have five desk phones that will regularly be used all at once, your network would need to support about 435 kbps (87 kbps x 5) when using the G.711 or G.722 codecs. In contrast, this measurement could drop to 235 kbps when using G.726.
  • Call Quality: Once you meet the necessary bandwidth requirement, you’ll want to adopt a codec with a high MOS. Your calls should sound good with an MOS of 3.8, but they will sound better with an MOS of 4.1.
  • Popularity: When calling other VoIP lines, your digital voice information may need to be transcoded if the receiver doesn’t support your chosen codec. If you use G.711 but the person you’re calling only supports G.726, the voice network will have to transform all the voice data sent between each user. This can add delay to your call, which can decrease your overall experience as a caller. Using a popular codec can increase the chance that you and your call recipient don’t have to transcode your data. It also gives you options when you want to use more than one type of phone in your office.

Let VirtualPBX Provide Codec Assistance

This isn’t the end of the conversation when it comes to codecs.

Your unique situation as a small business or enterprise Dash user will suggest which codec is right for your internet capability, number of users, phone use cases, and so on.

All our sales and support representatives can lead you through your unique technical situation. Whether you’re using VoIP for the first time or adding a set of new phones to your current Dash account, we’re here to help.

And if you’re looking for even more detail about the inner workings of a VoIP network, check out our comprehensive guide, “What is VoIP?”

How Circuit Switching Helps You Reach Customers

Telephone Pole - Circuit SwitchingIf you have the chance right now, take a look outside. You’ll probably find a few telephone poles on the nearest street. Those are the most salient example of circuit switching you will probably ever see.

Those poles and copper wires form the basis of the Public Switched Telephone Network (PSTN). Despite its age, the PSTN and its circuits remain a relevant part of communications for both homes and businesses. You probably couldn’t function effectively in the office for more than a few minutes without them.

Our Dash Business Phone System uses digital networks and packet switching primarily to initiate calls, but it makes heavy use of circuit switching along the way, like we discuss at length in our What is VoIP? guide.

Let’s consider one example to make circuit switching a more relatable topic: You make several calls from an IP phone connected to your Dash account.

Initiating a Call With Your IP Phone

How does your phone make the call? It first sends digital signals through the internet to VirtualPBX servers, which route the call to its destination. The hardware you use — including your IP phone, local network, and internet architecture — makes use of digital communication tactics rather than analog tactics.

VirtualPBX does a lot more here than just route your call. The particulars of this situation, however, all revolve around the fact that your IP phone acts like a computer. It sends packets of information just like a computer does.

Reaching Another IP Phone

Your desk or conference phone, when it sends your digital voice packets, can continue to use an all-digital, all-packet switched network to reach another IP phone.

Consider that your call reaches a business across town that uses a competitor’s VoIP service. Both Dash and the competitor’s plan all take advantage of the same underlying principles, so your call will likely continue to use packets throughout the entire journey from one phone to another.

Going Analog: Reaching a Home Phone

It’s easy, though, to jump out of the digital network and into the world of analog.

Consider that your next call reaches a customer’s home phone. If they use an analog phone service, a switching center will transform your digital packets into analog signals that the customer’s phone can understand.

Circuit switching occur at this point because the customer’s phone service must complete a steady circuit to hold a call.

The PSTN will make sure that your outgoing voice packets run through a circuit that’s completed within the copper cables outside the customer’s home. It will also make sure the reverse process happens when the customer speaks to you.

Circuit Switching is Here to Stay

Many of the calls you make to other businesses and to smartphones will have the chance to remain entirely digital. The PSTN has gone through a transformation where most of its switching centers and much of its hardware now uses digital signals to reach each other.

On the other hand, home phone users – which may represent a large portion of your customer base – will continue to make circuit switching a necessary element of the PSTN. No matter how digitally-focused the rest of the world becomes, the copper wires that line our streets will stay indispensable.

Packet Switching Plays a Key Role in Your Business

Packet switchingWhether or not you realize it, packet switching forms the backbone of business communications.

Packet switching – the aggregate process of sending and receiving groups of packets over a digital network – plays a prominent role when you:

  • Make a call on your Dash Business Phone Network
  • Use the internet to view a website
  • Send an email to a colleague
  • Watch a YouTube video on your phone

Packets act as the building blocks of every digital communications tool you use throughout the workday. Below, we’ll look at the ways in which packet switching exists in those tools.

For a deeper look at the technical aspects of VoIP and packet switching, check out our “What is VoIP?” guide.

What are Packets?

Digital networks – including your local computer network and the World Wide Web – use packets to transfer information. Packets are the small pieces of data that a digital network uses to move information from one device to another.

Briefly stated, packets exist as the pieces that comprise whole files. A bricklayer (the network) uses individual bricks (packets) to build a wall (the resulting file).

Each packet contains enough extra information to tell sending and receiving devices where the packet has been, where it should be sent, and in which order the device should assembled it with respect to the other packets.

A computer might not always receive packets as A, B, C and use them in that order to create a whole file. But it will know that A should be placed before B, and B before C, to create a readable result.

Packet switching is the aggregate process of sending and receiving groups of packets over a digital network.

Make a VoIP Phone Call

Business phone systems that use Voice Over IP (VoIP) to manage calls depend on underlying digital networks. Such systems use the Internet Protocol (hence, voice over IP) to send calls within a business’s local phone network and outbound to the public telephone network.

Your desk phones and conference phones send packets that contain voice information. They capture the sounds you make when you speak and convert those sounds into digital information that is eventually converted back into sounds on the receiving end.

VoIP phone system providers have to battle side effects of packet switching, including jitter and packet loss, that can affect the quality of voice calls. Providers use Quality of Service techniques to make their voice networks clear and reliable.

Viewing Websites and Sending Email Messages

When you view a webpage, you use packet switching to download packets from a central server onto your computer or phone.

Those files may be retrieved from the server in an abstract order. Your computer, however, knows from the information contained in the packets and the instructions provided by the website how to display the resulting page in your browser.

You also take advantage of packet switching when you send emails. The text you write in your Gmail or Outlook account will be broken down into small bits of information that are reassembled for your recipient so they can read your message as you intended.

Watching a YouTube Video

That business presentation (or cat video) you just watched on your phone’s data network also relies on packets.

The same processes described above apply to the data you send and receive on your 4G connection. Before you’re able to understand the audio and see the visuals, the digital network breaks down, sends, and pieces together your video in the same way it does to your website, email, and voice call.

Appreciate Packet Switching

The next time you use your computer or phone, try to remember the complex process that moves behind the scenes of all your tasks.

It should help you better appreciate the complexity of the internet and the VoIP phone system you use every day.

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