If 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
Circuit switching is connection-oriented. 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
Circuit switching also happens on your desk or conference phone. 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.