Ericsson manual Using Gprs In The T39

Using GPRS In The T39

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 “constantly” connected, as required by the appli- cation in use. If the user wants to send e-mail, it may be sufficient 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 specification includes four coding schemes with different data speeds. The T39 works with the first two coding schemes, but the data speed will naturally vary according to net- work configuration.

The GSM system's design limits the ability to use all eight time slots. Instead, the T39 uses up to three time slots for receiving data, and one slot for transmitting. This means the speed for receiving data is up to 39,600 bps and for sending data up to 13,200 bps.

Information about the identity of phone and the characteristics of the connection are described in the PDP context (Packet Data Protocol context). This information is stored both in the phone and in the mobile network, so that each phone is identified and “visible” to the system. In T39, multiple PDP context settings can be set via the menu system, or by OTA provisioning.

Using GPRS with the T39 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
	large files, images etc.
Cost efficient	GPRS being an IP-based connection means that a high transmission
	capacity is only used when needed. This makes it possible to stay con-
	nected via GPRS, whereas keeping a constant circuit switched connec-
	tion would be more expensive.
WAP over GPRS	Access the internet via WAP at high speed and with a constant connec-
	tion. The user can run the WAP functions such as browsing.
E-mail over GPRS	This means that the user can be connected to the e-mail system while
	reading and preparing messages, and that the messages are sent at a
	high speed.
Data communication	Using GPRS, this provides data and internet/Intranet access, for a PC,
	PDA or handheld device connected via Bluetooth wireless technology,
	infrared or cable.
Data and voice	The T39 can maintain a data connection when conducting a voice call.
	For example, the user can conduct voice calls while maintaining an
	uninterrupted connection to an e-mail system.
Provide settings	The GPRS configuration settings can be sent from the provider over
	the air, OTA. This way, the user can use GPRS without making any set-
	tings in the phone.

User controlled settings Full user control is enabled in the T39. In the Data connections menu, the user can set up multiple descriptions and access advanced settings for GPRS, for example Data compression and Quality of Service.

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