The hot news from the big wireless show in Cannes, France, is all about the convergence of traditional half-duplex radio walkie-talkies with VoIP-based wireless phones. They have been calling this "Push-to-Talk" (PTT), because that's all that a user had to do with traditional dedicated radio channels to initiate a voice connection with everyone else on the channel.

With inexpensive wireless VoIP networks creating individual person-to-person and group connections, Wireless guru Andrew Seybold thinks PTT may be the killer application for mobile voice communications service providers, and all the big wireless carriers have announced plans for offering the service to its subscribers.

Nextel has been the leader, until now, in offering PTT service to supplement its cell-phone services, and our David Zimmer has found it to be of great practical value in working in the field with a mobile team.

However, the new announcements by technology providers Comverse, Mobile Tornado and others, point to more of a similarity with IP-based Instant Messaging and presence/availability management for general voice communications than there is for specialized radio walkie-talkies.

I hesitate to use the label "Push-to-Talk" because the industry has already been using a similar term, "click-to-talk," to describe a more limited ability of a web site visitor (customer) to initiate either a telephone callback, or a VoIP-based voice connection with an enterprise contact center agent.

So, if you don't mind, I will use a more descriptive term, "instant voice messaging" (IVM), to discuss this convergence of voice messaging, Instant messaging and mobile phones. (Just what you need, another acronym!)

What Does "Instant Voice Messaging" (IVM?) Bring to the Table?

We have been expecting (and writing about) this development as a logical technology step in the evolution of unified communications (UC), since it's near real-time modality fits nicely between asynchronous text and voice messaging and conversational voice calls. Since voice is easier and much more time efficient than typing, it makes two-way message exchange much faster.

Voice also brings a personalized touch to messaging that makes it very attractive for consumer use. However, as with all forms of messaging, it has primarily been promoted by wireless providers as a means of drastically lowering the costs of wireless voice conversations between mobile frequent callers.

To quote Nextel, "Every time you push the button, it costs a fraction of what you might pay for a cellular call." Why else would a user put up with the annoyance of transmission delays and the "walkie-talkie," half-duplex style of voice conversation?

The driver of UC is personal communication management for all flavors of personal contact, including incoming and outgoing calls and messages. So, for openers, "IVM" lets both individuals and groups "immediately" initiate a near real-time messaging exchange in voice.

Similar to Instant (text) Messaging, in addition to exploiting the lower costs of VoIP networking, IVM will also require individual user presence and availability management for controlling access to a contact recipient.

Besides its role in mobile person-to-person contacts, we also see speech-based service applications exploiting IVM channels of contact. This will provide more immediate "push" delivery of voice-based time-critical alerts to mobile users, with instant voice responsiveness, whenever speech modality is indicated by a recipient's accessibility status (presence).

This would replace the traditional approach of an application process initiating a more expensive and cumbersome phone call. It would also let such applications be multi-modal and support either instant text or voice messages, all sharing the same benefits of presence management.

Exploiting IP network transport will not only make such applications inexpensive to use, but will also support more flexible and dynamic user interface choices for the next generation of multi-modal wireless devices.

Of course, the presence/availability management concepts of Instant Messaging (IM) apply even more strongly to voice interactions (vs. text messaging) with people, because of the transiency of speech output and its sensitivity to the users' surroundings. You can't listen or talk in a noisy environment, or talk when you may disturb a meeting or when the conversation must be kept private in a public space.

The 'buddy list" approach of IM will work particularly well for groups of users who communicate with each other constantly, and the wireless industry is targeting both consumer groups (youth and family market segments), as well as enterprise and organizational groups for mobile IVM services.

No Dialing, No Ringing - "Over and Out"

Comverse, in partnership with Mobile Tornado, demonstrated their "Push-to-Talk" solution last week at the GSM show in Cannes, France. Their offering will work across 2.5/3G, Wi-Fi, GPRS/1X/UMTS, IDEN and wired Internet networks, and provides a visual user interface for managing "presence-based" instant voice communications.

Following in the footsteps of traditional radio-based walkie-talkies, Comverse touted the ability of a user to "instantly talk or chat with individuals or groups - without dialing, ringing, or waiting for the other party to respond."

While person-to-person access to a recipient will be expected to be controlled though presence management facilities, we didn't see any mention of modality management (using either text or voice messages). We can't assume that because a user is carrying a speech-enabled device, that a speech exchange is "instantly" possible or appropriate for the recipient.

Also, while driving a car, a frequent mobile situation, a "push-to-talk" user interface may not satisfy the requirements of being eyes-free/hands-free. The latter situation should be able to exploit speech recognition voice commands.

The ability to start "talking ... without waiting for the other party to respond," is not always an appropriate thing for the contact recipient. This is where unified communications management must effectively help exploit the benefits of multi-modal handheld devices and user interface flexibility.

Fortunately, the IVM technology providers offer a choice of two modes of contact, which could be controllable by the recipient's "buddy list." Comverse lets the contact initiator choose an "Intrusive" mode to start talking directly to the other party, or a "Non-intrusive" mode to notify and invite the recipient to talk.

The Enterprise Perspective

From the Comverse announcement, their IVM offering is aimed at mobile operators and wireless carriers who want to "offer both standard cellular and Push-to-Talk (walkie-talkie) services that are targeted at the enterprise market, as well as the youth and family segments."

Because wireless transport outside of the enterprise domain will have to be a third-party network service (radio, 2.5G), mobile enterprise users will need such services for universal communication coverage. However, with the shift to VoIP transport, will such IVM capabilities also be practical for intra-enterprise IP networks? If so, we then face the traditional challenge of interoperability between enterprise communications ((CPE) and the carrier networks.

The hot news from the big wireless show in Cannes, France, is all about the convergence of traditional half-duplex radio walkie-talkies with VoIP-based wireless phones. They have been calling this "Push-to-Talk" (PTT), because that's all that a user had to do with traditional dedicated radio channels to initiate a voice connection with everyone else on the channel.

With inexpensive wireless VoIP networks creating individual person-to-person and group connections, Wireless guru Andrew Seybold thinks PTT may be the killer application for mobile voice communications service providers, and all the big wireless carriers have announced plans for offering the service to its subscribers.

Nextel has been the leader, until now, in offering PTT service to supplement its cell-phone services, and our David Zimmer has found it to be of great practical value in working in the field with a mobile team.

However, the new announcements by technology providers Comverse, Mobile Tornado and others, point to more of a similarity with IP-based Instant Messaging and presence/availability management for general voice communications than there is for specialized radio walkie-talkies.

I hesitate to use the label "Push-to-Talk" because the industry has already been using a similar term, "click-to-talk," to describe a more limited ability of a web site visitor (customer) to initiate either a telephone callback, or a VoIP-based voice connection with an enterprise contact center agent.

So, if you don't mind, I will use a more descriptive term, "instant voice messaging" (IVM), to discuss this convergence of voice messaging, Instant messaging and mobile phones. (Just what you need, another acronym!)

What Does "Instant Voice Messaging" (IVM?) Bring to the Table?

We have been expecting (and writing about) this development as a logical technology step in the evolution of unified communications (UC), since it's near real-time modality fits nicely between asynchronous text and voice messaging and conversational voice calls. Since voice is easier and much more time efficient than typing, it makes two-way message exchange much faster.

Voice also brings a personalized touch to messaging that makes it very attractive for consumer use. However, as with all forms of messaging, it has primarily been promoted by wireless providers as a means of drastically lowering the costs of wireless voice conversations between mobile frequent callers.

To quote Nextel, "Every time you push the button, it costs a fraction of what you might pay for a cellular call." Why else would a user put up with the annoyance of transmission delays and the "walkie-talkie," half-duplex style of voice conversation?

The driver of UC is personal communication management for all flavors of personal contact, including incoming and outgoing calls and messages. So, for openers, "IVM" lets both individuals and groups "immediately" initiate a near real-time messaging exchange in voice.

Similar to Instant (text) Messaging, in addition to exploiting the lower costs of VoIP networking, IVM will also require individual user presence and availability management for controlling access to a contact recipient.

Besides its role in mobile person-to-person contacts, we also see speech-based service applications exploiting IVM channels of contact. This will provide more immediate "push" delivery of voice-based time-critical alerts to mobile users, with instant voice responsiveness, whenever speech modality is indicated by a recipient's accessibility status (presence).

This would replace the traditional approach of an application process initiating a more expensive and cumbersome phone call. It would also let such applications be multi-modal and support either instant text or voice messages, all sharing the same benefits of presence management.

Exploiting IP network transport will not only make such applications inexpensive to use, but will also support more flexible and dynamic user interface choices for the next generation of multi-modal wireless devices.

Of course, the presence/availability management concepts of Instant Messaging (IM) apply even more strongly to voice interactions (vs. text messaging) with people, because of the transiency of speech output and its sensitivity to the users' surroundings. You can't listen or talk in a noisy environment, or talk when you may disturb a meeting or when the conversation must be kept private in a public space.

The 'buddy list" approach of IM will work particularly well for groups of users who communicate with each other constantly, and the wireless industry is targeting both consumer groups (youth and family market segments), as well as enterprise and organizational groups for mobile IVM services.

No Dialing, No Ringing - "Over and Out"

Comverse, in partnership with Mobile Tornado, demonstrated their "Push-to-Talk" solution last week at the GSM show in Cannes, France. Their offering will work across 2.5/3G, Wi-Fi, GPRS/1X/UMTS, IDEN and wired Internet networks, and provides a visual user interface for managing "presence-based" instant voice communications.

Following in the footsteps of traditional radio-based walkie-talkies, Comverse touted the ability of a user to "instantly talk or chat with individuals or groups - without dialing, ringing, or waiting for the other party to respond."

While person-to-person access to a recipient will be expected to be controlled though presence management facilities, we didn't see any mention of modality management (using either text or voice messages). We can't assume that because a user is carrying a speech-enabled device, that a speech exchange is "instantly" possible or appropriate for the recipient.

Also, while driving a car, a frequent mobile situation, a "push-to-talk" user interface may not satisfy the requirements of being eyes-free/hands-free. The latter situation should be able to exploit speech recognition voice commands.

The ability to start "talking ... without waiting for the other party to respond," is not always an appropriate thing for the contact recipient. This is where unified communications management must effectively help exploit the benefits of multi-modal handheld devices and user interface flexibility.

Fortunately, the IVM technology providers offer a choice of two modes of contact, which could be controllable by the recipient's "buddy list." Comverse lets the contact initiator choose an "Intrusive" mode to start talking directly to the other party, or a "Non-intrusive" mode to notify and invite the recipient to talk.

The Enterprise Perspective

From the Comverse announcement, their IVM offering is aimed at mobile operators and wireless carriers who want to "offer both standard cellular and Push-to-Talk (walkie-talkie) services that are targeted at the enterprise market, as well as the youth and family segments."

Because wireless transport outside of the enterprise domain will have to be a third-party network service (radio, 2.5G), mobile enterprise users will need such services for universal communication coverage. However, with the shift to VoIP transport, will such IVM capabilities also be practical for intra-enterprise IP networks? If so, we then face the traditional challenge of interoperability between enterprise communications ((CPE) and the carrier networks.