Although not particularly fancy, the Alpine CDA-9857 stereo head unit provides a solid foundation for adding a multitude of other Alpine components with its Alpine AI-Net interface. In our test setup, we installed the CDA-9857 and added on the Alpine KCT-100BT Bluetooth module and the Alpine KCE-422i Full Speed cable, which connects to an iPod. The CDA-9857 is a single-DIN head unit with a single CD slot that reads MP3 and WMA discs. There is no auxiliary or USB input, although, like the Bluetooth support, these can be added via the AI-Net interface. We were impressed with the ease of navigating MP3 CDs and iPods, and especially with the Bluetooth module's ability to stream music from a cell phone.
The front of the CDA-9857 stereo holds a two-line monotone display, a large volume/selection knob that can recess into the unit, and navigation and function buttons. The CD slot sits behind the faceplate, which must be flipped down to access the slot. This arrangement has become pretty standard on aftermarket car stereos and presents little hassle. The faceplate feels solid as it flips down, and you can remove it easily to discourage theft.
Three buttons sit to the left of the volume knob that control searches through music sources. These buttons work in concert with the volume knob, using it for rotary selection. The button structure works well for navigating sources with large amounts of music. With an iPod, the buttons and knob navigate by playlist, artist, album, or song. On a WMA or MP3 disc, the buttons navigate folders or files. The preset buttons for the radio also help navigate the iPod.
Six buttons, lit up in blue, sit to the right of the volume knob. These encompass standard play and skip track functions and control source and menus. The buttons are nicely accessible, but the more frequently used play button should swap places with the menu button.
The KCE-422i iPod cable uses a dedicated plug in back of the head unit, so an installer will have to find a convenient spot to run it into the cabin of the car. Likewise, the KCT-100BT Bluetooth module plugs into the back of the unit and presents a more difficult installation, as it is comprised of a square black case, a wired remote, and a wired microphone. The main part of the module, the black case, has a blue LED on top that indicates when it is in Bluetooth reception mode. The downside of this design is that the module should be mounted visibly in the car cabin, where it will stick out.
The back of the CDA-9857 unit has leads out for four speakers and generates 18 watts per channel. It also has three sets of RCA jacks for output to speaker and subwoofer amps.
Streaming cell phones
Our test setup allowed a good array of music sources, such as iPod, CD, and radio, but the most interesting was the A2DP (sometimes referred to as Bluetooth 2.0) connection between the KCT-100BT Bluetooth module and a cell phone. For our test, we used the Sony Ericsson K790A phone, which also supports A2DP. Once we established the Bluetooth connection, the CDA-9857 head unit worked as a hands-free speaker for the cell phone and also amplified MP3s played on the cell phone through our test-bed speakers. Even better, the radio preset buttons on the head unit can play, pause, or skip tracks on the cell phone. The manual for the Bluetooth module says that not all phones will have this degree of integration.