Sony Ericsson T628, T630 manual Modem and AT commands, GSM data communication

•Take advantage of full user control in the data connections menu, establishing multiple descriptions and accessing advanced settings for GPRS.

White Paper T630/T628

Interruption of GPRS data account

When the user is browsing with a T630/T628 the GPRS connection will be automatically discon- nected when an incoming call is received. This is the default behaviour. However, it is possible for operators to customize the phone in such a way as to ensure that the user is asked if they wish to remain connected when an incoming call is received.

Modem and AT commands

The T630/T628 contains a complete GSM/GPRS modem. This provides data and e-mail communi- cation, as well as Internet/intranet access, for a connected PC, PDA or handheld device. Once the PC/PDA is connected to the phone using a cable, Bluetooth wireless technology or infrared, 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 T630/T628, AT commands are used for:

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

•configuring and requesting settings and behav- iours in the phone, from a connected PC or PDA

GSM data communication

The built-in data capability turns the phone into a modem when connected to a PC/PDA. The T630/ T628 offers the user data connection anytime, any- where, unmatched by fixed telephone networks. Each GSM channel is divided into eight repeating time slots. A normal GSM voice or data call is cir- cuit switched, and only one time slot is used for each call. The data speed is therefore limited to 9,600 bps.

GPRS enables constant connection and high speed

With GPRS, the connection is maintained “con- stantly”, and data is transmitted in packets. Pricing 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 85,600 bps download speed.

High Speed Data gives a faster speed

High Speed Data (HSCSD) increases speeds for circuit switched data by allowing the phone to use a coding scheme with a high capacity, and 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.

35 October 2003