Sony Ericsson P802 manual Technical Explanation of CSD, Hscsd and Gprs, Circuit Switched Data CSD

For Internal Use Only	P800 Smartphone
	White Paper, May 2002

Technical Explanation of CSD, HSCSD and GPRS

This section provides an overview of the way data communication works in a GSM network environment. This will help you to understand the characteristics of the different solutions supported by the P800 and the parameters which govern the data transmission speeds available.

Circuit Switched Data (CSD)

A modem and landline is a common way to connect to the internet and company networks. The modem establishes a telephone call to the remote server which is ‘circuit-switched’, meaning that a telephone circuit is maintained for the duration of the connection, irrespective of whether data flows or not. The connection has a fixed bandwidth and is normally charged on a connected-time basis.

Server

Circuit-Switched Network

In GSM networks, this facility is widely available and is called Circuit Switched Data (CSD). It is very similar to using a modem, but is subject to lower data transmission speeds due to the connection taking place over the GSM wireless network. The standard speed of operation for CSD is 9.6kbps transmit and receive. 14.4kbps is available in some GSM networks. The P800 will operate at the higher speed where it is available.

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