VoIP Cellphones: The Call of the Future

by Toni-Sama

I was talking to a tech buddy of mine during a visit home when the subject of VoIP-enabled cell phones came up.

He was insistent that the technology would never come to pass because it simply wouldn't be profitable.  I argued, saying it was the next logical step, and to prove him wrong I've done a bit of homework.  Now I don't think the technology is widely available (or hacker-friendly) yet, but with a host of manufacturers (Nextel, Sprint, Qualcomm, and Motorola) planning and developing VoIP-friendly handsets, I think we should prepare for this technology jump.

What is VoIP?

VoIP is simply "Voice over Internet Protocol," a stem of the Network Voice Protocol from the days of ARPANET.

It's a fairly neat little thing, utilizing an IP-connected computer and a Plain Old Telephone Service (POTS) line.  The computer connects to a web site, which receives the POTS number from the computer, then connects to the POTS line through the Private Branch Exchange (PBX).  The connection can also be through a dedicated system (or adapter), or even through a built-in converter.  VoIP has been widely utilized by existing phone networks for the transfer of data, which has given way to the "unlimited local calling plans" of the major telephone companies.

Now, obviously, cell phones don't have a built-in IP connection, so the connection comes from one of two sources: Unlicensed Mobile Access or Session Initiation Protocol.

UMA is the "easy" choice because it utilizes Bluetooth technology to connect to the PBX.  UMA works very well with Global System for Mobile Communications (GSM) operators, and can also switch between VoIP and cellular networks easily.

Unfortunately, as a downside of this ease, it's also a bit pricier and it's currently only available on phones with Bluetooth technology, a la Motorola RAZR V3 and the Motorola V560.

BT Group, out of Great Britain, offers packages that utilize VoIP when the customer is at home.  In return for using VoIP, the price is lower when the network is used.  The prices can get as low as 55 pence for an entire hour of use.

SIP is the other choice, although it s certainly less popular.  SIP utilizes a Wi-Fi router to connect to the Internet, which then utilizes Real-Time Transport Protocol (RTP) to communicate with a SIP router.

The SIP router interacts with the Public Switched Telephone Network (PSTN) and the communication runs from there.  The benefit of this technology is that it connects to the PSTN via a software standard, not requiring a home router.

Unfortunately, you can currently only call other utilizers of the technology because of the G.711 standard.  Likewise, only certain phones can use the software (Nokia E60, E61, and E70).

The State of the Technology

To my knowledge, only two companies offer VoIP cellular service.

The first is the aforementioned BT Group, which offers service in Great Britain.  It utilizes a home service plan and for the price of roughly U.S. $120 you get a phone, modem, and a calling plan.

BT's phones use UMA.  The other company offering this is Truphone, a company offering a beta test of the SIP for the Nokia E-Series phones, with downloads coming soon for the N-Series (N80, N91, N92, and N93) and Windows Mobile compatible phones.

The technology isn't going to be limited for long, though.  Phillips Semiconductors is manufacturing UMA chips for cell phones, Texas Instruments is coming out with WiLink 4.0, Ericsson is manufacturing UMA phones, and Qualcomm, Nortel, Verizon, and Sprint are all using a protocol called "EV-DO Revision A."

Motorola, through Skype, is planning releases this spring, and this technology is soon to be popular.  At present, the more popular option is to run over a managed network, versus an unmanaged network (i.e., the Internet) due to voice quality concerns.

Uses and Abuses

Now if you're a hacker, you understand the great potential behind this.

Cellular technology is going to be cheaper and possibly even free (to begin with, since VoIP isn't currently regulated).  Of course, you'll still have to contend with quality, and international calls are going to be funky (as per usual), but with the benefit of cellular service you won't have to worry about finding an active connection should you really need to make a call, perhaps in an emergency situation.

Also, because of the modern technology of these phones (Truphone programs their software in C++ on Symbian), these things could possibly be tweaked, allowing data transfers as well as digital voice communication.

In the future, you might watch more than TV on your cell phones, perhaps acquiring audio/video communication.  Think instant global video, with real-time audio.  You could communicate with your boss in China as you organize your meeting in New York.  You could chat with your international exchange student in Germany from your home in Canada.  Soldiers could talk to their families and loved ones face-to-face.

Hell, organize a conference with your guild buddies on WoW.  See concerts live from other countries.  The possibilities are limitless.

However, there are some negatives to it at this time.

If you live outside of the United States or Great Britain, you face some difficulties.

In Ethiopia, VoIP is illegal.  In India, you can't make a VoIP gateway.  Likewise, many Latin American and Caribbean countries have imposed restrictions on VoIP due to government-owned phone companies.

Also, at this time location registration for VoIP isn't mandatory and can't easily be determined from the calling phone.

As a result, Caller ID will seldom work if it works at all.  It could also easily be spoofed from a VoIP "land line," so presumably it could be spoofed from a cell phone.

In addition, most consumer VoIP networks don't support encryption, so phone calls could be intercepted and even changed.  This should be legislated soon, since government is extremely interested in regulating this new form of communication.

Know what I'd love to see?  Articles giving more detail on the actual processes of communication over VoIP and POTS, and some really detailed tech specs on VoIP-ready phones.

So, all you phreaks out there, get crackin'.

Thanks to Google, O'Reilly, Truphone, BT Group, Wikipedia, and Anthony, who inspired this work.  Shout-outs to Jessika, Billy, Bean, Gendo, and Troy.