The class of the device determines the speed at which GPRS can be used.
For example, the majority of GPRS terminals will be able to download data at speeds of up to 24Kbps (kilobytes per second). At the higher end, speeds are theoretically possible up to 171.2 kbit/sec when 8 slots are assigned at the same time to a single user. In reality 40-50Kbps.
PC cards capable of GPRS will send data up to speeds of 48Kbps.
Compare this to current data speeds available:
| Type |
Uplink (Sending) |
Downlink (Receiving) |
| GPRS |
14 kbps |
28-64 kbps |
| GSM CSD |
9.6-14 kbps |
9.6-14 kbps |
| HSCSD |
28 kbps |
28 kbps |
| Dial-UP |
56 kbps |
56 kbps |
| ISDN Standard |
64 kbps |
64 kbps |
| ADSL |
256 kbps |
512 kbps |
| Broadband |
2 Mbps |
2 Mbps |
Multislot classes are product dependant, and determine the maximum achievable data rates in both the uplink and downlink directions.
Written as (for example) 3+1 or 2+2, the first number indicates the amount of downlink timeslots (what the mobile phone is able to receive from the network).
The second number indicates the amount of uplink timeslots (how many timeslots the mobile phone is able to transmit).
The active slots determine the total number of slots the GPRS device can use simultaneously for both uplink and downlink communications.
| Multislot Class |
Downlink Slots |
Uplink Slots |
Active Slots |
|
1 |
1 |
1 |
2 |
|
2 |
2 |
1 |
3 |
|
3 |
2 |
2 |
3 |
|
4 |
3 |
1 |
4 |
|
5 |
2 |
2 |
4 |
|
6 |
3 |
2 |
4 |
|
7 |
3 |
3 |
4 |
|
8 |
4 |
1 |
5 |
|
9 |
3 |
2 |
5 |
|
10 |
4 |
2 |
5 |
|
11 |
4 |
3 |
5 |
|
12 |
4 |
4 |
5 |
Futher Examples:
| Class 2 |
|
Class 4 |
| One Up, Two Down - (2+1) |
|
One Up, Three Down - (3+1) |
| 8-12Kbps Send - 16-24Kbps Receive |
|
8-12Kbps Send - 24-36Kbps Receive |
Mororola Accompli A008
Trium Mondo, Sirius |
|
Motorola TimeportT260 |
|
|
|
| Class 6 - Configurable between |
|
Class 8 |
| Two Up, Three Down |
|
One Up, Four Down |
| 16-24Kbps Send - 24-36Kbps Receive |
|
8-12Kbps Send - 32-40Kbps Receive |
| Or Three Up, Two Down |
|
Ericsson T39, R520
Motorola v60i, v66i
Samsung Q200, S100
Siemens S45, ME45, M50
Trium Eclipse |
| 24-36Kbps Send - 16-24Kbps Receive |
|
| Nokia 6310, 6510, 8310 |
|
|
|
|
| Class 10- Configurable between |
|
Class 12- Configurable between |
| One Up, Four Down |
|
One Up, Four Down |
| 8-12Kbps Send - 32-48Kbps Receive |
|
8-12Kbps Send - 32-48Kbps Receive |
| Or Two Up, Three Down |
|
Or Two Up, Three Down |
| 16-24Kbps Send - 24-36Kbps Receive |
|
16-24Kbps Send - 24-36Kbps Receive |
| Philips Fisio 820 |
|
Or Three Up, Two Down |
|
|
24-36Kbps Send - 16-24Kbps Receive |
|
|
Or Four Up, One Down |
|
|
32-48Kbps Send - 8-12Kbps Receive |
|
|
Sierra Wireless Aircard 750
GSM/GPRS PC Card |
The class indicates the mobile phone capabilities.
Class A
Class A mobile phones can be connected to both GPRS and GSM services simultaneously.
Class B
Class B mobile phones can be attached to both GPRS and GSM services, using one service at a time. Class B enables making or receiving a voice call, or sending/receiving an SMS during a GPRS connection. During voice calls or SMS, GPRS services are suspended and then resumed automatically after the call or SMS session has ended.
Class C
Class C mobile phones are attached to either GPRS or GSM voice service. You need to switch manually between services. (52RD.com) |
