An initial glance at the Samsung SPH-A640 doesn't reveal much about what's inside. Even the tiny camera lens located at the top of the handset is relatively unobtrusive. Covering the entire flap is a black plastic face that acts as mirror. Some might like its austerity, but we weren't fans--the plastic feels cheap, and it attracts finger smudges easily. Though you might think there's no external display, a quick press of the volume rocker activates the postage-stamp-size screen in the center of the flap. Though it's monochrome, it displays the date, time, battery life, signal strength, and caller ID (where available). It doesn't support photo caller ID, but it functions as a rudimentary viewfinder for self-portraits. Unfortunately, none of the display settings are customizable.
Inside the phone is the 1.75-inch (128x160 pixels) TFT display. Typical of Samsung displays, it's bright and vivid, with support for 65,000. However, that means it's difficult to see in direct light. You can set the backlighting time, the greeting, the dialing font and size, and the brightness. You also get three menu style choices, and it's one of the first Samsung to show the company's new menus. While previous Samsung menus were known for their animation and graphics-heavy interface, the new menus are designed with simplicity in mind. There's still a bit of animation in one of the styles, but our favorite choice showed only a plain background with a simple grid of choices laying on top. In this case, less is more.
Below a rather large hinge are the navigation controls, which are in typical Samsung style as well. A five-way toggle with an OK button in the center acts as a shortcut to four user-defined functions. There are also two soft keys, a dedicated Back button, and the standard Talk and End/power keys. The backlit keypad buttons are flat of the surface of the phones, but they're big enough and spaced sufficiently far apart. On the left spine is the PTT button, a covered headset jack, and the aforementioned volume rocker, while a camera key and the voice-dialing button sit on the right spine.
The Samsung SPH-A640's phone book is rather small at 300 contacts, but each entry holds five phone numbers, e-mail and Web addresses, a nickname, and a short memo. You can assign callers to groups, pair them with one of 9 monophonic or 20 polyphonic (32-chord) ring tones, or assign them a photo for caller ID. Keep in mind, however, that the image will not show up on the external display. There's also a separate Ready Link address book that holds 200 personal contacts and 200 work contacts. Other dialing features include voice and speed dialing and three-way calling, as well as call forwarding and call waiting. And like the Samsung SPH-A580, the SPH-A640 supports Sprint's new wireless backup service.
The handset's other offerings should be enough to satisfy everyone but the most demanding cell phone users. You'll find a daily event reminder, a scheduler, a task list, a countdown timer, a memo pad, a world clock, a calculator a vibrate mode, text and multimedia messaging, and a speakerphone. There's also Bluetooth for connecting to headsets, but save for an electronic business card, you can't use it for sending files wirelessly.
The VGA camera takes pictures in three resolutions (640x480, 320x240, and 160x120), and you can choose from three quality settings (Fine, Normal, and Economy). Other features include a 5- or 10-second self-timer, five color tones, 10 fun frames, brightness and white-balance settings, a zoom, and four shutter sounds, though no silent option. When finished with your shots, you can save them to the phone's memory, upload them to an online album, or send them in a multimedia message. Picture quality was quite admirable for a VGA camera. Though colors weren't terribly bright, they were still distinct, and object outlines were sharp. Amateur directors are out of luck, however, as the SPH-A640 does not support video recording.
You can personalize the SPH-A640 with a variety of screensavers and alert sounds. If you want more options or ring tones, you'll have to download them via the WAP 2.0 wireless Web browser. A number of trial applications and demo versions of five Java (J2ME) games are included as well, but you'll have to buy the full versions for extended play.
We tested the dual-band, dual-mode (CDMA 800/1900; AMPS 800) SPH-A640 in San Francisco using Sprint's service. Call quality generally was good, with sharp clarity and adequate volume. Occasionally, callers sounded robotic, but it was nothing particularly bothersome. On their end, callers could tell we were using a cell phone, but they didn't report any problems. Speakerphone calls were marginally worse if we were inside, but outside in noisy situations, it was hard to hear at all. We paired the phone with the Plantronics Explorer 320 Bluetooth headset and enjoyed acceptable call quality, but the volume was somewhat low.
The Samsung SPH-A640 has a rated talk time of 3.8 hours, and we managed to eke out 4 hours of talk time in our tests. Our standby time tests resulted in 11 days of battery life. According to FCC radiation tests, the SPH-A640 has a digital SAR rating of 1.23 watts per kilogram.