Bells may have the monoply over FTTH, but they have something to worry about in the interim: people who are letting go of their fixed lines in favor of cell phones exclusively. Research conducted on behalf of Nokia shows that nearly 45 million people in US, UK, Germany, and South Korea have switched exclusively to mobile handsets for all or most of their voice calls. Fixed-to-Mobile Substitution (FMS) is the hot new trend, and is only going to gain momentum. Analysts say nearly one third of U.S. wireless customers won’t have residential landline phone service by 2008. It makes sense as more people get fed up with paying two phone bills–when they’re using their cell phone almost exclusively. For instance, I came across this little gizmo from Telular and Sprint. Telular’s Phonecell terminal links all of the home’s phone jacks to the Sprint PCS network, so customers can use existing home phone devices (cordless phones, fax machines, TiVo boxes) just as before. They can also bundle the terminal in the same package with their mobile phones, and benefit from the cost savings and convenience of one phone bill. There is even a GSM version of the product. (The Phonecell has Telular’s patented RJ-11 interface that emulates the local phone company, providing dial tone and services such as Caller ID, Call Waiting and Call Hold. The new product includes GPSOne positioning technology for E-911 Phase 2 compliance.) I saw similar devices in India, which were simple fixed CDMA home phones.