Samsung Electronics and audio product maker Bang & Olufsen on Tuesday unveiled their latest joint music-mobile phone, Serenata, which holds 4GB of songs and has a number of other music features similar to the iPhone.

The handsets will go on sale in Europe by the end of the month, said Anthony Lee, a spokesman at Samsung. Pricing has not yet been determined.

The handset doesn't look much like a mobile phone; the top half is dominated by a navigation wheel, and the designers having dispensed with buttons. The 2.26-inch LCD touch screen is below the navigation wheel, in the place where the buttons are found on conventional mobile phones.

The navigation wheel is intended to be used one-handed. All primary functions on the phone are controlled by the navigation wheel, including searching menus, dialing, writing, and accessing music lists, the companies said. The touch screen is secondary.

A button on the handset switches it quickly from music to phone mode, and the screen changes from red to blue to make sure the user knows exactly what mode the handset is in.

The handset has a built-in speaker and bass system, and can play amplified music for up to five hours through the speaker or for around 13 hours through a headset before requiring a battery charge, the companies said in a news release.

The amount of song storage space is a major difference between Serenata and the iPhone. Apple has already said it will only sell 8GB iPhones in the future, once it sells out of the 4GB version.

Samsung believes the 4GB on Serenata, capacity for about 1,000 songs, is enough for most users, said Lee. There is no way to increase the memory capacity of the handset, he added.

The phone will work with GSM networks in the 900,1800, and 1900 MHz bands, and with HSDPA (High-Speed Downlink Packet Access) services on 3G networks. Users can send e-mail SMS text messages from the handset, and store up to 1,000 phone numbers in its address book. The phone allows users to create to-do lists and write in calendars, and it has enough battery power for three hours of talk time.

Serenata is an update to the Serene music-mobile phone the two companies put out two years ago.