Behind the battery cover are the microSD card slot and a SIM card so you can use the phone overseas.
The strength of the ES400S lies in its enterprise-friendly features. You can access all of your company's back-end systems like inventory tracking and placing orders for new equipment, depending on what sort of apps your company uses. You can scan bar codes, as we mentioned above, and you can also get signatures for orders by having your customer sign directly on the phone.
Of course, the ES400S also has all of the usual Windows Mobile features. That includes Internet Explorer Mobile, Microsoft's My Phone backup service, MSN Messenger, Windows Live, MSN Weather, MSN Money, Bing, and the full Microsoft Office Mobile suite. It supports Microsoft's Direct Push technology for e-mail, tasks, calendar, and contacts via your company's Exchange server. You can also use your own POP3 and IMAP e-mail addresses if you wish. Other preinstalled apps include Remote Desktop Mobile, SMS Staging, MSP Agent, Rapid Deployment Client, Airbeam Client, and Sprint Navigation, Sprint's turn-by-turn directions app and service. You can get more apps via the Windows Marketplace.
Aside from that, the ES400S has all the normal PIM functions like a calendar, an address book, a calculator, a speakerphone, conference calling, voice command support, a notebook, and text and multimedia messaging. The ES400S is also a dual-mode phone that can connect to both GSM and CDMA networks as long as you have a SIM card inserted in the back. This dual 3.5G broadband connection lets you toggle between Sprint's 3G EV-DO network here and a GSM UMTS/HSDPA network abroad. The ES400S also has Wi-Fi and Bluetooth 2.1 with A2DP streaming.
Even though it's a business-centric phone, the ES400S still has Windows Media Player. You can load MP3, AAC, AAC+, WMA, MIDI, MPEG4, WMV, H.263, and H.264 file formats to the phone via either USB mass storage or a microSD card. The phone takes cards of up to 32GB.
The Motorola ES400S has a 3.2-megapixel autofocus camera that can take pictures in three resolutions and three quality settings. You can capture panoramic images by stitching photos together, and there's a shutter timer option too. For notation purposes, you can geotag your photos, and add comments to them. There's a video camera as well.
Photo quality was average on the whole. Images seemed slightly fuzzy, and colors looked dull and dark.
We tested the Motorola ES400S in San Francisco using Sprint Nextel. Call quality was fantastic. There was very little hiss or static from either end. We heard our callers very clearly, and their voices sounded as if they were in the next room.
Similarly, callers praised our audio quality highly. They did say our voice quality was a bit harsh at times, but it wasn't a huge distraction. They said we had great volume, so that they had no trouble hearing us even when we were walking on a busy city sidewalk in the rain. Speakerphone quality was impressive as well, though callers did detect a tiny bit of an echo at times.
The phone has a 600MHz ARM 11 processor, and while that may sound underpowered, we experienced no hiccups or delays when launching multiple apps. Some apps did take longer to load, however--the GPS app took a few more seconds than we expected, as did the browser.
Surfing the Web was a pleasant experience for the most part. The EV-DO speeds served us well, and we loaded the CNET home page in around 18 seconds. We weren't able to test the GSM 3G speeds.
The Motorola ES400S has a rated battery life of 6 hours of talk time and 10 days of standby time. It has a tested talk time of 6 hours and 32 minutes. You can also purchase a battery that will extend the talk time to 12 hours and the standby time to 12 days.