An important feature of GPRS terminals (cell phones) is that they belong to one of the 3 functional classes:
1. Class C: only possible data transfer. Such terminals already on the market in the form of a PCMCIA card (a special device installed in a special slot in the computer or in a jacket pocket for a computer, and provides
mobile Internet access), or handheld computers, organizers. However, their choice is limited.
2. Class B: terminals enabling transmission and voice and data, but not both. In general, it is conventional mobile phones with built-in GPRS modem. Most terminals sold today are of this class.
3. Class A: terminals that provide both voice and data simultaneously. This means that it is possible, and talk, and to seek information on the Internet at the same time. Such terminals are not yet available on the market, but it is expected that they will be executed in the form of handheld computers.
Also, it is necessary to note one of the most important cell phone and network settings - the number of channels to receive data when using GPRS.
The feature of GPRS phones is not only what they make available GPRS services, but also the fact that their characteristics currently determine the maximum rate of receiving / data transmission. GPRS technology allows you to use channels that are not occupied at the given time, voiced connections. The more channels are free from voice transmission, the higher the data transfer rate via GPRS can be achieved. Currently, the maximum bandwidth of one channel 13.4 kbps. But the number of channels supported by the terminals available on the market is limited: three, four (40.2, 53.6 kbps) to receive data and one, two to transfer (13.4, 26.8 kbps).
Class 6 - the ability to work with 3 channels for receiving and 2 channels for transmission, but no more than 4 channels total.
Class 8 - is the ability to work with four channels for receiving and one channel for transmission, but no more than 5 total channels.
Class 10 - is the ability to work with 4 channels for receiving and 2 channels for transmission, but not more than 5 in all channels.
GPRS Beeline
At this point, Biline GSM network is able to provide five channels for reception and one for transmission. In the very near future, it will be provided the opportunity to network to work already with 2 channels for transmission.
GPRS in the MTS
GPRS-terminal class describes the number of time channels, which is supported by software. You can use GPRS-terminal of any class. From the beginning of MTS GPRS network commercial operation is maintained until 4-time channels to incoming and outgoing traffic.
GPRS into a megaphone
Terminal classes differ in the number of time slots used to transfer data. In the network MegaFon, the maximum possible number of slots that subscriber - 4 may receive information (DOWNLINK) and 1 to send (Uplink). Maximum data transfer rate by each time slot - 12 kbps., I.e.Maximum speed of information is obtained - 48 kbps. In the network, priority has voice traffic. And depending on the workload of the base station, the number of slots used to transmit data can decrease.
Also useful information
reference.