The small, 17-button remote control is uncluttered and easy to use but doesn't include shortcuts such as artist, title, and genre buttons--or clearly labeled play or pause keys. Instead, you use the four-way keypad and its center-mounted enter button to navigate music categories, directory levels, and track lists. A volume up/down button facilitates connecting the DSM-120 directly to PC-style powered multimedia speakers that don't have a volume control of their own, but the volume buttons adjust only the level of the analog stereo output, not the digital output. Page-up and -down buttons enable rapid navigation of long track lists, but the absence of an alphanumeric keypad means you can't skip directly to a specific artist or track, for instance.
Setting up the D-Link DSM-120 is straightforward. From the included CD-ROM, you install D-Link Media Server, select the audio file types you want to make accessible for playback via the DSM-120, point the software to the PC directories where your audio files are stored, then wait while the software scours your hard drive. The application took just more than four minutes to index approximately 1,500 audio files located on our PC's hard drive. To finish up, connect the DSM-120 to your stereo's audio inputs, power on, select your wireless network from the list, enter the network's 64- or 128-bit WEP encryption key if it uses one (WPA encryption isn't supported), and select the DHCP or static IP address option based on your network configuration. We were prompted to download new firmware, which took only a couple of minutes to self-install. If you add a hard drive to the DSM-120, you'll also need to install D-Link File Manager, a well-designed utility that enables transferring tracks between your PC and the DSM-120 via its Ethernet port, 802.11g/b wireless, or USB 2.0. Furthermore, to stream DRM-protected WMA files to the DSM-120 (songs that you purchase from online music stores such as Musicmatch), you'll need to run the free Windows MediaConnect software in lieu of the D-Link's Media Server. When we switched to Windows Media Connect, the DSM-120 was instantly recognized, verifying its UPnP (Universal Plug and Play) compatibility. In terms of file-format support, the D-Link DSM-120 covers the key bases. In addition to playing the requisite MP3 files, it's compatible with WAV and WMA files. This includes DRM-protected WMAs such as those you'd purchase from most Internet music stores, including Napster and Musicmatch, as well as "rented" DRM WMA files downloaded as part of a "to-go" subscription plan. Furthermore, as with every non-Apple digital audio receiver to date, the DSM-120 can't play protected AAC files purchased from the iTunes store, nor can it play nonprotected AACs. M3U and PLS playlists are supported, but you can't create playlists on the fly with the device's controls or its remote. The DSM-120 offers genre-, artist-, and album-based navigation for tracks stored on a networked PC, but not directory-based. For tracks located on the device's local hard drive, navigation is only by directory. Internet radio support is limited to Live365, an all-around solid service with free and subscription-based listening options. Unfortunately, unlike the pricier, video-capable DSM-520, the DSM-120 isn't capable of streaming music from the Rhapsody subscription service, a favorite of ours.
We wish D-Link offered a version of the DSM-120 with a preinstalled hard drive, but that shouldn't stop those with a hair of technical savvy from taking the plunge. Our test unit arrived with a hard drive preinstalled, but in order to add one yourself, you'll need a 2.5-inch IDE model, and you'll have to connect the drive to your PC and format it first. If you don't install a hard drive or connect a device via USB, the DSM-120's capabilities will be limited to streaming tracks from networked PCs and playing Internet radio. The great thing about having a hard drive in the unit is that local file playback avoids problems such as audio dropouts that are commonly associated with streaming music over a wireless network. Furthermore, you don't need to power up a PC when you want to listen to some music. It's very convenient that you can transfer tracks to the DSM-120's hard drive via an 802.11g/b connection. That said, the process goes much faster if you connect the unit to your network using an Ethernet cable. For example it took 7.5 minutes to transfer an album's worth of MP3 files (60MB) over 802.11g, but only 3 minutes to transfer the same album via an Ethernet connection. On another note, if the DSM-120 was capable of streaming tracks to UPnP-compliant client devices (such as the Roku SoundBridge units and other DSM-120s), it would be a viable DIY alternative to music servers such as the Olive Musica and Escient Fireball E2 that cost more than $1,000. The D-Link DSM-120's analog outputs sound suitably clean and distortion-free, and the optical digital output works as advertised, passing bits to an A/V receiver without issue. The DSM-120's ability to stream music from connected USB devices was less successful, however. It proved capable of streaming and transferring tracks from our old RCA Lyra flash player but not from a hard drive-based Cowon iAudio M5 or flash-based Samsung YP-1U. Likewise, it had trouble recognizing many of the MP3-laden USB thumbdrives that we plugged in. But the bigger disappointment for most users is that it can't interface with iPods of any type.
We tried using iTunes and Musicmatch as the DSM-120's UPnP server applications, but it didn't work with either. Unless you're a die-hard iTunes user, that shouldn't be too big a deal, because D-Link's own server application and Windows Media Connect are both quite adequate--just point them to your relevant iTunes directories. The device sometimes take a couple seconds to load screens, which can be annoying if you have a large PC-based file collection and are trying to scroll through a long track list, for instance.
Wireless performance was a mixed bag. In one location, the DSM-120 was frequently burdened by dropouts and stutters despite the fact that it was in the same room as our wireless router, or in another room just 20 feet away. These problems sometimes occurred even when the unit's indicator showed full signal strength and in locations where the video-enabled step-up model, the D-Link DSM-520 and the Roku SoundBridge M500, experienced rock-solid performance. That said, we retested the DSM-120 in two other locations utilizing three other wireless routers (two D-Links and one Netgear), and experienced solid wireless connectivity for hours on end. Bottom line: Your wireless mileage may vary.
We like the D-Link DSM-120 for its innovative feature set, including connectivity to USB drives and MP3 players, and for it expandability through the addition of an optional internal hard drive. We'd like to see firmware updates smooth out some of its rough edges, such as navigation quirks, wireless stability, and compatibility issues with USB devices, but if you can find the DSM-120 for less than $150, it's not a bad deal.