Xeta Group
(Plain Old Telephone Service)
Making the move from PSTN to SIP Trunk:
The trusted old Public Switched Telephone Network (PSTN), with its Analog lines, ISDN BRI, E1 or T1 lines, are gradually being replaced by IP telephony. An increasing number of businesses are using more modern and flexible SIP Trunks.

The major telecom providers are fast phasing out the old PSTN functionality, and are moving customers to IP. The majority of businesses these days are already using modern IP phone systems and SIP trunks, although some smaller business may still rely on outdated technology.

What Is A POTS Line And How Does It Work?

What Is A POTS Line?
POTS (Plain Old Telephone Service) is basically an analog voice transmission phone system implemented over copper twisted pair wires. It is the phone line technology most of us grew up with at home and is exactly what you think it is: copper wires dangling overhead, carrying your voice from one place to another. The phrase "phone line" is often used, even in an era when more and more businesses are starting to rely on modern telephone systems like VoIP. In essence, a phone line is the quintessential definition of the traditional landline phone system which relies on a physical wire. Hence the term line. The name given for this traditional telephone service is POTS (for plain old telephone service).

POTS networks were created to facilitate voice communication over copper cables that traversed countries and continents, and it has been the standard voice-grade telephone system used by residences and businesses across the world since the 1880's. But the POTS most of us are familiar with is an upgrade over the rudimentary phone system invented by Alexander Graham Bell.

POTS is a retronym for voice-grade telephone service employing analog signal transmission over copper loops. POTS was the standard service offering from telephone companies from 1876 until 1988 in the United States when the Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) was introduced, followed by cellular telephone systems, and voice over IP (VoIP). POTS remains the basic form of residential and small business service connection to the telephone network in many parts of the world. The term reflects the technology that has been available since the introduction of the public telephone system in the late 19th century, in a form mostly unchanged despite the introduction of Touch-Tone dialing, electronic telephone exchanges and fiber-optic communication into the public switched telephone network (PSTN).

History OF POTS
The first phone lines were suspended across poles, traversing the entire country. But advancements in technology has seen many of those lines buried underground. So why were they hung in the first place?
Initially, POTS was known as the Post Office Telephone Service. This is because, in the early days, callers relied on post office operators to connect them to their intended destinations. The service was later taken from the hands of national post offices, and the term Plain Old Telephone Service was adopted. You may sometimes find POTS service being referred to as the public switched telephone network, or PSTN for short. This is basically the same thing, although the latter is mostly used in geeky telecom circles.

How A POTS Line Works
The POTS setup has remained virtually the same for decades. There have been many upgrades to usher components of the POTS telephone system into the digital era, but the copper wire connection has weathered the storm. As far as the mechanics of a POTS line go, this phone service works by establishing a dedicated circuit between Point A and Point B for the duration of a transmission. Originally, communication between two parties depended on an operator to manually connect them for the call. But the aspect of switching has been automated, and today the system is almost entirely digital.
What Is POTS And How It Works
How POTS Works
The telephone handset converts the sound waves of a caller's voice into electrical signals. The signals then travel from the telephone to a "drop cable" that connects the residence or business to an outside terminal.
The terminal consolidates calling signals from the immediate neighborhood for transmission through an aerial cable to a central office.
Computerized switches inside the central office decipher the electronic signals to determine where to route the
Depending upon the destination of a call, the signal may be routed to a regional hub, called a tandem office, where it is forwarded to a distant central office for further transmission. Alternatively, the signal may be routed through a cable that feeds directly to a central office near the destination of the call.
The central office's switches again read the incoming signal and route the call to the appropriate terminal. From the terminal, the call is transmitted to the local lines that connect the network to a home or business.
The telephone handset then reconverts the electrical signal into sound waves, and the call is completed.
Technology Behind POTS
Let's take a closer view into how a POTS network actually works. Back in the days of early telephony, establishing a connection between two parties that needed to connect required stretching wires between them. Yes, much like a tin can telephone, albeit over longer distances.Obviously, this meant the longer the distance, the steeper the costs. With the emergence of POTS lines, this cost was knocked down some.

One-way PSTN managed to achieve this was by placing switches at centralized points in the network. These switches acted as communication nodes between any two points in the network. To connect one phone to another, a telephone call is routed through one or more switches operating on a local, regional, national, or international level.

But voice as we speak it cannot transmit through the POTS line. The sound waves from a caller's voice need to be converted into electrical signals in order to flow through the network. This falls on the telephone handset on both the caller's and receiver's ends. The copper line is susceptible to interference, and the signal is also prone to get weak where long distances are involved. For this reason, amplification may be called for along the way.

The early copper network only transmitted analog signals, which require a dedicated circuit since they travel in a continuous stream. This can be both a blessing and a curse. On the upside, a dedicated circuit is as reliable as circuit technologies come. But it is handicapped by the fact that the line has to be reserved for one call and one call only. This type of switching is what is known as circuit switching.

Circuit Switching
Back in the old days, circuit switching was the reason you needed an operator's assistance when making calls. In those days, operators would sit by one giant wooden switchboard, plugging copper wires into a common patch panel. In the case of connections that required two exchanges, two operators would go about simultaneously plugging the caller's and receiver's wires into the same inter-exchange wire. This wire was known as a "trunk". Long-distance calls were unbearably costly because calling long distance was akin to renting the use of a very long piece of copper wire each time you wanted to make a call.

As technology advanced, so too did circuit switching. The first stab at automated switching came in 1891 following the invention of the Strowger switch. It was also known as a step-by-step (SWS) switch due to its operational features. Later, it pressed into service after the invention of the rotary dial. It changed once, and then twice, finding favor among the masses. Eventually, it was phased out by the crossbar switch. Despite their reliability, crossbars were faulted for being complicated, bulky, and costly.
You can only imagine how challenging it must have been to provide excellent customer service under those conditions back then.

Enter The Transistor
Thankfully, a disruption came in the form of one of the best things to happen to the world since man bashed two stones together to ignite a fire: the invention of the transistor. The transistor heralded the electronic exchange era, which slowly paved the way for the digital network. Current phone lines have been upgraded to carry digital signals in the form of "packets." Packet-based technology does not dominate the transmission channel by demanding a continuously open and dedicated circuit, unlike its analog counterpart. Rather, it uses the underlying network to transmit voice (and data) messages independently through the switches.

A copper line is a bi-directional 64Kbps service capable of carrying human voice both ways at the same time (i.e. full duplex). However, it has a limited frequency band of 300 to 3400 Hz, meaning it cannot transmit digital signals which are in the form of "0s" and "1s". For this to happen, a critical hardware component needs to be added to the PSTN.

Enter The Modem
This is a device that was designed to exploit the digital nature of the public switched telephone network without overhauling your entire phone system. This should come as good news for small business owners who are not planning to upgrade their analog communications systems any time soon, especially considering the wealth of options available on the market.

1. DSL (Digital Subscriber Line) technology makes it possible to transmit data over your copper-wire telephone system. A transceiver connected to your personal computer uses the local telephone network to connect to an ISP's network.

The network in turn routes data to the World Wide Web.
This type of service is most popular among small business setups. Why? Because it provides just enough bandwidth for a sizable number of users to access the Internet.

2. ISDN (Integrated Services Digital Network), ISDN is another technology that allows digital transmission over a regular telephone line. ISDN makes it possible to transmit both voice and data over a single copper line. To establish a network connection, users have to dial in. The fees are determined by the duration of the transmission.

ISDN promises faster call setup and higher quality calls compared to the classic telephone system. Businesses also prefer it because it comes with the option of integrating with other phone systems (PABX). This allows them to take advantage of a host of other features. For example, using a 100-number range, queues, groups, on-hold music, etc. It is ideal for larger businesses or those looking to expand in the near future.

How Much Does A POTS LIne Cost For Business?

POTS lines are traditional analog phone service businesses use for voice, fax, DSL and alarm lines. A POTS line can cost anywhere from $20 to $60 dollars per month and we have seen as much as $85. Business phone lines are the dumping grounds for tacked on fees. A $40 a month business line typically carries another $10 in fees and surcharges. That's a 25% markup, and that's not counting sales tax or subsidy charges.

It's easy for businesses to turn their focus away from POTS because it seems to be a low cost service, especially compared to a MPLS network or a GigE internet connection, but a large corporation could be spending thousands of dollars a month for their inventory of POTS lines.

5 Ways To Reduce The Cost Of Your Business Phone Lines

1. Business Phone Line Elimination – Modem lines are a thing of the past. Fax lines are headed in the same direction. Alarm lines can be replaced with wireless connections that carry fewer fees and surcharges. Inventory your POTS lines and eliminate the lines that you no longer need.

2. Business Phone Line Repricing – If the majority of your POTS lines are with the same incumbent phone company, contact your account rep and inquire about volume pricing. If your carrier rep claims that bulk pricing doesn't exist, work through a telecom consultant who has an agency relationship with that carrier. Telecom consultants act as customer advocates and have to prove their value. If volume pricing is available, a telecom consultant will make you aware of it.

3. Business Phone Line Transformation – If you have a number of POTS lines at any given location, it might pay to convert them to PRI or SIP Trunks. PRI offers 23 channels, which can be shared by a number of employees. For example, 40 POTS lines could cost $2000 a month. 40 employees could share one PRI, which would cost about $500 a month. POTS lines could also be converted to SIP. SIP stands for Session Initiation Protocol. SIP trunks are voice paths over the internet and they're less expensive than POTS lines or PRI circuits and carry fewer taxes and surcharges.

4. Business Phone Line Aggregation or Managed SIP Trunking – If you are a large, multi location company and you have hundreds of POTS lines spread out across the country, supplied and billed by different carriers, POTS consolidation is something you should consider. POTS aggregators can provide one bill and one point of contact for your entire POTS inventory. This can greatly reduce the administrative costs related to the service. The other option is moving to Managed SIP Trunking since SIP Trunking is not location specific and you can get the exact number of channels needed and share across sites.

5. Move To A Modern Business Communications System – Most businesses have or are in the process of migrating from analog to IP telephony. A lot of this has to do with the fact that VoIP offers more cost savings compared to its traditional counterpart. Moving to VoIP can save businesses as much as 60% in telecommunications costs.

If you would like help inventorying, auditing, managing and lowering the cost of your Business Phone Line inventory, contact Xeta Group today.
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