The term PSTN, short for Public Switched Telephone Network refers to traditional telephony, which uses copper wires to transmit analog voice data from one location to another.
This is in contrast to newer networks using data lines to transmit voice data, known as Voice over IP (VoIP). In some circles, PSTN is referred to by the acronym "POTS," which stands for Plain Old Telephone Service.
While PSTN dates back to 1800s, today's PSTN systems utilize digital switching, including the trunks that connect the exchanges.
The only exception to this is the line that runs from the exchange to the home or office, which utilizes a digitized analog signal. Although many Americans now use VoIP and wireless telephony for communications, PSTN networks still power an estimated 33% of homes.
PSTN vs. VoIP
In recent years, VoIP has seen a growth surge due to its affordability and scalability. However, PSTN maintains a loyal customer base.
Here are just a few advantages PSTN has over VoIP:
- Call quality – VoIP call quality can be spotty at times, especially during peak traffic hours. PSTN generally remains unaffected by other users on the system.
- Reliability – If the power goes out, VoIP will be unavailable along with the rest of a business's network. PSTN phones operate separately from a business's power, although cordless phones may not work in a power outage.
- Emergency Services – In an emergency, a VoIP line may be untraceable, while a PSTN line can be traced to the location.
However, it's important to consider both sides and to note that VoIP has some benefits over PSTN, as well:
- Cost – Although there may be an initial cost for a business to switch fro PSTN to VoIP, once in place, businesses can often enjoy a substantial monthly cost savings over PSTN systems.
- Scalability – One of the most popular features of VoIP is its scalability. Lines can easily be added as a business grows and if a user moves, the number and phone can go with that person.
- Extra Features – Advanced features like call forwarding or call transferring can incur extra fees with PSTN, whereas they're available for no extra charge on VoIP.
Due to these advantages, many small businesses opt for VoIP. Larger businesses without PSTNs already in place will often be tasked with choosing between the two types of phone systems and hopefully comparing the two against each other will help in that process.
PSTN's reliability can sometimes make it a more attractive option, but in some cases, a PSTN gateway may be the best choice.
PSTN Gateways (PSTN Via VoIP)
Businesses can have the best of both worlds by taking advantage of gateways that connect a VoIP system to a PSTN.
An FXO VoIP gateway is added to a business's network to act as a bridge between the IP network and the PSTN. The FXO gateway handles converting calls to the appropriate delivery system before it reaches its recipient.
For enterprises with multiple locations, each branch will need its own gateway to handle calls. Businesses will be required to choose the number of gateways it will need at each site and additional ports will need to be added as the number of users increases.
The Future for PSTN and Business
Despite its continued use, U.S. regulatory bodies have had discussions about phasing out the PSTN. Service providers are behind this measure, with supporting parties aiming for a 2018 sunset of PSTN telephony.
Legislators are concerned about systems that rely on PSTN to operate, including credit card processing and alarm systems. Experts are already concerned about the lack of 911 tracing on IP-based lines, especially in rural areas, where GPS navigation signals have difficulty getting an exact location through GPS navigation.
While each system has its benefits and drawbacks, businesses have plenty of options when choosing a phone system. Whether a company opts for PSTN, VoIP, or a VoIP gateway on a PSTN system, it's never been easier to implement a full-scale, affordable phone system.