Did you know our telephone network dates back more than 100 years? Often known as POTS (plain old telephone system), it’s what the industry calls a “legacy technology” and was developed from the original system invented by Alexander Graham Bell in 1876.
Built on copper wires, the network was designed to carry telephone calls over long distances and was fully bi-directional. The downside? It was limited to a bandwidth of 300 to 3300 Hz.
Despite the limited bandwidth, the legacy system was capable of delivering voice services very reliably compared to wireless networks and was later capable of fax communication.
As the system expanded the telephone companies began using fiber optic for the backbone of their networks, due to its greater capacity and speed. As the fiber optic system is digital this required equipment to convert the old POTS analog signal.
Once the Internet arrived there was demand to bring it into the home using the existing telephone network. This initially involved using modems that converted the digital signal to analog, but speeds were very slow and severely limited the usefulness of the Internet.
Later, ISDN and DSL technologies were introduced and used the Internet Protocol (IP) language.
Now demand has increased to the point where millions of subscribers are expecting TV, broadband, video, data and voice, all at the highest speeds possible. In response, the phone companies are pushing to eliminate POTS altogether and switch to an IP-based system.
What does this mean for the broadband industry?
The transition to IP means an all-digital process that is more conducive to using fiber. Fiber networks have the advantage of almost unlimited capacity. Copper is limited by the actual electrical conductivity of the wire, whereas fiber is simply transmitting a signal using light waves.
Fiber is much more reliable. The electrical conductance of copper can be affected by moisture and corrosion as well as from the wire being stretched, bent or broken. Fiber has a much greater pull strength and is not susceptible to the elements. However, it does require specialized connections and methods of routing and storage to maximize signal quality.
Fiber is also unlimited in the kind of signal it can send whether it be data, audio or video. It can easily adapt to changes in protocols and is not liable to interference from other sources.
It’s not surprising then that the telephones companies are pushing to abandon the old legacy copper system and move to all IP-based fiber optic networks. For example, after Hurricane Sandy the old copper infrastructure was destroyed by wind and flooding. It was mostly replaced with fiber, which will not be affected by salty air and less liable to damage from storms.
This switch, from legacy to fiber, means huge savings for telephone companies. Verizon recently converted seven of its central offices to fiber and found it can reduce its real estate space by 60 to 80%. On top of that, the telco estimates that fiber is 70 to 90% more reliable.
There are drawbacks from shifting away from the old system. Copper can do something fiber can’t: it can conduct electricity.
With the old system, 48V DC is sent along the phone line so that in the case of power outages the phone can still connect to emergency services. With fiber there can also be problems connecting certain emergency calls and monitoring services including alarm systems and medical alert devices.
Another issue is that by switching systems the telephone companies are moving basic phone service out of the common carrier provisions of Title II that did not apply to Internet service. A recent FCC ruling said it should be covered, yet some phone companies plan to appeal the decision.