User's Manual

AC65/AC75 Hardware Interface Description

Confidential / Preliminary

AC65/AC75_hd_v00.372 Page 42 of 118 2006-08-03

3.4 Automatic EGPRS/GPRS Multislot Class Change

Temperature control is also effective for operation in EGPRS Multislot Class 10 (AC75 only),

GPRS Multislot Class 10 and GPRS Multislot Class 12. If the board temperature rises close

to the limit specified for normal operation

while data are transmitted over EGPRS or GPRS,

the module automatically reverts

• from EGPRS Multislot Class 10 (2Tx slots) to EGPRS Multislot Class 8 (1Tx),

• from GPRS Multislot Class 12 (4Tx slots) to GPRS Multislot Class 8 (1Tx),

• from GPRS Multislot Class 10 (2Tx slots) to GPRS Multislot Class 8 (1Tx)

This reduces the power consumption and, consequently, causes the board’s temperature to

decrease. Once the temperature drops by 5 degrees, AC65/AC75 returns to the higher

Multislot Class. If the temperature stays at the critical level or even continues to rise,

AC65/AC75 will not switch back to the higher class.

After a transition from EGPRS Multislot Class 10 to EGPRS Multislot Class 8 a possible

switchback to EGPRS Multislot Class 10 is blocked for one minute. The same applies when

a transition occurs from GPRS Multislot Class 12 or 10 to GPRS Multislot Class 8.

Please note that there is not one single cause of switching over to a lower Multislot Class.

Rather it is the result of an interaction of several factors, such as the board temperature that

depends largely on the ambient temperature, the operating mode and the transmit power.

Furthermore, take into account that there is a delay until the network proceeds to a lower or,

accordingly, higher Multislot Class. The delay time is network dependent. In extreme cases,

if it takes too much time for the network and the temperature cannot drop due to this delay,

the module may even switch off as described in Section 3.3.4.1.

See Chapter 5.2 for temperature limits.