I see that another attempt is being made to drive a stake through the heart of the two-wire plain old telephone service (POTS), also known as the Public Switched Telephone Network (PTSN). This time it is by Alcatel-Lucent and its PSTN Smart Transform.
Alcatel-Lucent says its PSTN Smart Transform consulting and design services to current POTS providers who want to shift to all voice-over-IP network will reduce migration costs 30–50%, reduce end-user outage time during migration of 20 seconds compared to an average of 20 minutes by competing services, and migrate 99% of their end-users without experiencing issues.
If this plan makes it to my PTSN provider I will probably be one of that 1% who will have “issues,” no matter who is doing the conversion because I have just shifted back to a standard two-wire POTS line from my local telephone company. After numerous tries with different companies, I gave up voice-over-IP (VoIP) because it was maddeningly unreliable. And I find nothing in the material on the Alcatel-Lucent website describing Smart Transform that makes me regret that decision. The web page presents a good case to telephone service providers but there is little on what it means to end users.
Limits of IP-based telephony
Based on my experience with Voice over IP (VoIP) systems over the last several years, I don’t have much confidence in the all-IP solution Alcatel-Lucent is proposing. Here’s why:
When you place a “regular” phone call using the Public Switched Telephone Network (PSTN), you use what's called circuit-switched telephony. This system works by setting up a dedicated channel (or circuit) between two points for the duration of the call. These telephony systems are based on copper wires carrying analog voice or digitized versions of it over dedicated circuits from the home to a local central office where it is further compressed and transmitted as a whole to the receiving location.
VoIP, in contrast to PSTN, uses what is called packet-switched telephony. Using this system, the voice information travels to its destination in countless individual network packets across the Internet. This type of communication presents special TCP/IP challenges because the Internet wasn't designed for the kind of real-time and deterministic communication a phone call represents.
While PTSN-based POTS provides only limited features, low bandwidth, and no mobile capabilities, it has something that after my experiences with VoIP I now value more than I used to: dial-tone availability — that is, a live line — 100 percent available, always or as close to that is as humanly possible. That is due in part to a totally battery-backed up network independent of the power grid. Previously in the United States, when AT&T/Bell was a regulated semi-private company, such backup was government mandated. Now, even though they are no longer government regulated, many of the local telecom companies (BabyBells) that were spun off after deregulation still use it on their PTSN systems, especially in rural areas in the Midwest and inner west of the United States.