Home network equipment maker D-Link entered the mobile phone market Tuesday, introducing a new line of "V-CLICK" handsets that work with both traditional GSM operators as well as Wi-Fi networks. Users can switch between the technologies with a click of a button.

As wireless hotspots become more ubiquitous, phone manufacturers have turned to building handsets that are able to utilize Internet connectivity for making calls over VoIP. The idea is that such calls are cheaper than traditional cellular calling, especially when dialing internationally. In addition, Wi-Fi coverage could help areas where cellular signals are limited or non-existent.

Theoretically, a user could hop onto a Wi-Fi network when in range and save money, as well as ensure their call won't drop while indoors. The problem, of course, has been perfecting such a capability, as handing off a call between a cellular and Wi-Fi network has proven quite complicated. T-Mobile, however, has been testing such a service in the northwest United States with positive results.

The D-Link V-CLICK features tri-band GSM support (900/1800/1900 MHz) and a two-inch 176x220 pixel color screen. The handset includes Opera Mini for browsing the Web and logging into Wi-Fi hotspots. D-Link has not specified whether the phone will work with existing VoIP providers, only saying that users will be able to configure a specific SIP profile.

"The market for dual-mode phones looks very promising, and the more than 10 years we've had in researching and developing 802.11 wireless and VoIP technologies make this a natural extension of our product offerings," said D-Link CEO Steven Joe.

The V-CLICK is unlocked, meaning it can work with any wireless provider that uses GSM, including Cingular and T-Mobile in the United States. GSM is the primary wireless technology in Europe, and D-Link says its phones will work with any pre-paid or standard SIM card.

Battery life of the phone is about 5 hours of talk time using GSM and 2 hours over Wi-Fi. Standby time was not detailed, but D-Link says users can turn off the Wi-Fi to conserve power. The initial V-CLICK model is scheduled to ship early next year at a retail price of $599.99 USD.