To set up the 2400 handset, we followed the quick reference guide to insert the batteries, plug in the charger, and register the handset with the base system. There is no need to plug the 2400 into a telephone jack, as it connects wirelessly through the base system. (We used the Siemens 2420 cordless communications system in our tests.) The batteries need to charge for eight hours prior to using the handset.

The functions available through the handset depend on your base system. The eight physical buttons (in addition to the usual 0 through 9, #, and *) on the handset let you answer or dial external and internal numbers, transfer calls, and display the menu-driven soft function keys. With soft keys, you can place a call on hold and answer another, retrieve held calls, page other handsets or the desk station, answer calls placed through another handset, join an ongoing call, change phone lines, listen to answering system messages, access a call log, and much more. The handset also displays caller-ID and call-waiting information. You'll want to read your base system's documentation for a complete description of the available functions.

Talk time is approximately four hours, and standby time is about 36 hours on two fully charged AA batteries (ni-cad batteries included; optional lithium-ion AA batteries have a longer life). The charger also has recharging space for spare batteries. The handset has internal antennas to help protect it from damage. In addition, the handset design includes headset jacks for hands-free use; however, the handset's light weight and slim profile make it more comfortable to hold than any cordless phone we've tested.

In our tests of the 2400, sound quality was very good thanks to the phone's 32 Kbps adaptive differential pulse code modulation (ADPCM) digital signal. The sound was only slightly softer than our corded reference desk phone. The sound quality was static- and interference-free until about 130 feet from the base, where the signal began to break; the signal broke up significantly at 420 feet, and the handset became unusable at 530 feet. These results compare reasonably well to Siemens' rated usage distance of 150 feet (indoors) to 1,500 feet (outdoors under ideal conditions), but do not compare well with less expensive 900 MHz digital spread spectrum (DSS) phones that we've tested.

Within reasonably close proximity to the base, you'll get the same clear reception and frequency-hopping-spread-spectrum security offered by Siemens's other 2.4 GHz phones. All you need to add the Siemens 2400 2.4 GHz cordless handset to your system is an electrical outlet--additional jacks and wiring are not required. --Mike Brown

Pros:

• Very clear signal
• Lightweight and comfortable to hold
• Very easy to set up and use

Cons:

• Less range than typical 900 MHz DSS phones