Seybold’s Take - A Second Life for Push-to-Talk?

Sat, 12/03/2011 - 1:56pm
Andrew Seybold

Public safety still uses PTT, but there’s another group of citizens who may one day discover the joys of instant one-to-one and one-to-many communications thanks to VoIP and cross-network connectivity.

Old-fashioned push-to-talk has come to commercial networks in a big way. I say “old-fashioned” because the first land mobile radios that were put into police service in the 1930s used push-to-talk technology. The land mobile radio community has not changed much over the years and push-to-talk is still operated the same way it was then. The advantages of push-to-talk are many, especially for groups of people who need to communicate quickly and easily.

Andy SeyboldPush-to-talk (PTT) offers fast setup of a session (less than one second) and there is no dialing or other setup involved. You push the button and talk, release the button and listen. This form of communications is vital to public safety, of course, but public safety must continue to have its own networks designed for mission-critical voice communications. Even so, there are many others who can benefit from push-to-talk over cellular systems. You might recall that Nextel’s cellular network supported push-to-talk from the beginning and still does today, although the network is being phased out over the next few years. This means that the 10 million or so Nextel users have to find an alternative to the Nextel network. Sprint is now offering voice over IP push-to-talk over its CDMA network, Verizon is offering this service on its network, and soon, I have heard, AT&T will be upgrading its own push-to-talk network capabilities to be more competitive with the other network operators.

There are several other groups that are very interested in VoIP PTT, including the millions of users of non-public safety land mobile radio (LMR) systems. Some of the systems must be upgraded before Jan. 1, 2013, to narrow the voice channel used from 25 KHz down to 12.5 KHz in order to make more LMR channels available since the spectrum allocated to LMR systems is already overcrowded. Some of these users will be moving to commercial VoIP systems and the commercial network operators are making it easy to transition by offering IP bridges between existing LMR systems and commercial push-to-talk systems.

Push-to-talk services have expanded over the years and today on a commercial network it is possible to have a one-to-one PTT conversation and one-to-many, which is important for many groups that work closely together. Most services involve oneto-many talk groups. A talk group is a pre-defined group of co-workers or others who need to communicate with each other. The commercial networks support talk groups of upward to 100 people and multiple talk groups so that conversations can be directed to only those who need to be involved in them. Another advantage of VoIP PTT on commercial networks is that there is a “presence” indication, which means on your wireless device you can see if the person or people within a group you want to communicate with are also on the system to receive the transmission.

One area of growth for VoIP PTT that has not yet been addressed by any commercial network is the teen market. Teens like one-to-many text, IM and other forms of data communications. It seems to me that if they were aware of one-to-many almost-instantaneous voice communications, they would flock to it. VoIP PTT is inexpensive on the commercial networks, and I can envision a group of teens keeping in contact in that manner as well as by text. However, if it is to be marketed to teens and others who may benefit from VoIP PTT services, it will have to be capable of being used not only on a specific commercial network as it is today but also across networks in the future.

If you go back in the history of commercial wireless or cellular, you will see that when SMS or text messaging was first introduced, it was on a network-by-network basis with no cross-network connectivity. It was used but not as much as it is today because now it does not matter what network a person is on, he/she will receive a text message from anyone else that sends a message to his/her phone number. The same was true for MMS or multimedia messaging services, which started out as an on-network technology but was not widely used until the networks permitted MMS to be multi-network. Voice has always been capable of calling any phone in the world, wireless or wired, but it was not that long ago when roaming between networks was either not possible or expensive. Today we don’t even think about roaming in most cases. We arrive in a location, turn on our devices, and dial a number.

Therefore, I contend that in order for VoIP PTT to become a more accepted mode of voice communications on the commercial networks, it will have to work across networks. This becomes more difficult than the other forms of cross-network communications because each network is presently using a VoIP PTT technology that is unique to its network and each is being provided by a different vendor. Still, it will be possible to make this work. IP gateways will need to be developed between networks, and some type of back-end system will need to be put into place as was done for voice, text and MMS. I am convinced that the result will be the elevation of VoIP push-to-talk from a niche category to being attractive to a much larger wireless population.

Today you have to buy a phone with VoIP PTT capability already built in, and the types of these devices are sparse and the choices few. However, in the near future it will be possible to enable any phone or device on the wireless network by simply downloading a VoIP client and assigning a key to push-to-talk. That’s when we will see the VoIP PTT population explode.

Many of the younger customers on commercial wireless networks don’t have a clue what PTT is or why it would be of benefit. They grew up in a world with wireless phones. Once they understand the value of instant, one-to-one and one-to-many voice communications, I believe they will adopt it quickly and the PTT segment of the commercial wireless market will grow as long as there are provisions for cross-network push-to-talk.

Seybold heads Andrew Seybold Inc., which provides consulting, educational and publishing services. For more information, visit


Share this Story

You may login with either your assigned username or your e-mail address.
The password field is case sensitive.