Specifications

The R520 contains a complete GSM modem. This provides data and e-mail communication, as

well as Internet/Intranet access, for a connected PC, PDA or handheld device. Once the PC/

PDA is connected to the phone using Bluetooth wireless technology, infrared or a cable, and the

appropriate software is installed, the modem in the phone works in a similar way to a PC Card

modem, or an external modem.

In the R520, AT commands are used both for:

¥ controlling the data communication between the PC and the remote service

¥ conÞguring and requesting settings and behaviours in the phone, from a connected PC or

PDA

The built-in data capability turns the phone into a modem when connected to a PC/PDA. The

R520 offers the user data connection anytime, anywhere, unmatched by Þxed telephone net-

works. Each GSM channel is divided into eight repeating time slots. A normal GSM voice or

data call is circuit switched, and only one time slot is used for each call. The data speeds are

therefore limited to 9,600 or 14,400 bps.

High Speed Data (HSCSD) increases speeds for circuit switched data by allowing the phone to

use two time slots for receiving data. The download speed is increased to up to 28,800 bps. The

speed for sending data is limited to 14,400 bps. The data rate can be increased several times by

the use of rate adaption, interworking with ISDN. This also provides additional features, such as

quick call set-up capability.

With GPRS, the connection is maintained ÒconstantlyÓ, and data is transmitted in packets. Pric-

ing of GPRS can be dependent on the actual use of bandwidth, which means very low cost when

no data is sent or received, while the phone remains connected. When transmitting large

amounts of data, bandwidth can be increased automatically to allow faster transmission speed,

up to 53,600 bps download speed.

GSM

9.600 or 14.400 bps

9.600/14.400

13.400

HSCSD

19.200 or 28.800 bps

GPRS

53.600 bps