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White Paper T630/T628
35 October 2003
• Take advantage of full user control in the data
connections menu, establishing multiple
descriptions and accessing advanced settings
for GPRS.
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.
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.
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.