From the outset, you can see that the SPH-A420 won't win any beauty contests. Completely straight lines and sharp corners give it an almost perfectly rectangular shape, while the silver color and black band won't catch envious looks on the street. On the upside, the phone is compact (3.4 by 1.7 by 0.8 inches) and lightweight (2.9 ounces), so it slips easily into a pocket and won't weigh you down. Also, the construction is solid, and we felt comfortable holding the phone while talking. We're surprised, however, that phone manufacturers are continuing to pump out models without external displays. We realize it may save a few dollars, but that means you must open the SPH-A420 to see your caller's identity.
Flip open the mobile, and you'll find a standard Samsung internal display. Measuring 1.6 inches diagonally (128x160 pixels) and supporting 65,000 colors, it's quite serviceable for a phone of this caliber. Colors are sharp and the screen bright. You can change the backlighting time and the dialing font size and color, but other screen-editing options are not available. Also, like the Samsung SPH-A640, it's one of the first handsets to support Samsung's new menu designs.
The SPH-A420's navigation array has a typical Samsung design. A four-way toggle surrounds a central OK button and doubles as a shortcut to four user-defined functions. The other controls included two soft keys, the talk and end/power buttons, and a back key. There's also a dedicated speakerphone key, which is a nice touch. The keypad buttons are flat with the surface of the phone, so it's somewhat hard to dial by feel. They're decently sized, though, and they benefit from a bright backlighting. The only exterior features are a volume rocker and a covered headset jack on the left spine and a tiny green light on the front flap that blinks for incoming calls.
The SPH-A420's feature set is minimal, but keep in mind simplicity is the overall theme here. The phone book holds 300 contacts with room in each entry for four phone numbers, an e-mail address, and a memo. You can organize callers into groups or pair them with one of 10 monophonic or 35 40-chord polyphonic ring tones. You can assign a photo, but since the SPH-A640 doesn't have a camera or a Web browser and doesn't support multimedia messaging, you're out of luck if you don't like the preloaded graphics. Other features include a task list, a scheduler, an event reminder, a countdown timer, a memo pad, a world clock, a calculator, an alarm clock, and text messaging. Voice features include voice memos and dialing a speakerphone that you can activate before you make a call. Strangely, there's an airplane mode, but we can't imagine why you'd want to use it.
You can personalize the SPH-A640 with a variety of screensavers, greetings, and alert sounds. But there's no wireless Web browser, so you're stuck with the options already on the phone. You don't get any games either.
We tested the dual-band, dual-mode Samsung SPH-A420 in San Francisco using Sprint's service. Call quality was good overall, though voices on our end sounded a bit tinny. Callers reported the same conditions, but they weren't bothered too much. The volume level was satisfactory as well, but we had a bit of trouble understanding our friends in very noisy environments. Speakerphone quality was about the same; calls were audible and noisy on our end, but callers usually asked that we switch to a normal call.
The SPH-A420 has a rated talk time of 3.5 hours, which we met in our tests. Our standby battery test came to 11.5 days. According to FCC radiation tests, the Samsung SPH-A420 has a digital SAR rating of 1.32 watts per kilogram.