Specifications

The R520 supports GPRS (General Packet Radio Services), which means that the data is sent in

packages at a very high speed. The phone remains connected to the network all the time without

using any transmission capacity, until data needs to be sent or received. This illustration gives a

comparison.

¥1. A normal GSM voice or data call only uses one of eight repeating time slots in the GSM

channel. Data speeds are therefore limited to 9,600 or 14,400 bps

¥2. With HSCSD (High Speed Circuit Switched Data), the phone uses two time slots for receiv-

ing data, increasing the data speed for receiving data up to 28,800 bps

¥3. In GPRS, data is sent in packets, and one or several time slots can be combined to provide

the necessary bandwidth, up to 53,400 bps for receiving data

Instead of occupying a whole voice channel for the duration of the call, data is sent in small

packets as needed, just like IP on the Internet. Capacity is used only when data is being sent or

received, which means that it is possible to be ÒconstantlyÓ connected, as required by the appli-

cation in use. If the user wants to send e-mail, it may be sufÞcient to share a channel with sev-

eral other users. On the other hand, the phone has access to several time slots if a higher

capacity is needed.

The GPRS speciÞcation includes four coding schemes that allow data speeds of 9,050 bps,

13,400 bps, 15,600 bps and 21,400 bps, respectively. The R520 works with all coding schemes,

but the data speed will naturally vary according to network conÞguration.

The GSM system's design limits the ability to use all eight time slots. Instead, the R520 uses

three or four time slots for receiving data, and one slot for transmitting. This means the speed

for receiving data is up to 53,400 bps and for sending data up to 13,400 bps.

This gives several advantages, for example:

Constant connection Keep an open connection to the e-mail system or the company net-

work, staying online to receive and send messages at all times. All con-

nection settings can be managed by using the Data connections feature.

High speed Gain access automatically to increased bandwidth when downloading

GSM

9.600 or 14.400 bps

9.600/14.400

13.400

HSCSD

19.200 or 28.800 bps

GPRS

53.600 bps