User's Manual
Table Of Contents
- Contents
- Figures
- Tables
- Document history
- Introduction
- Product concept
- GSM application interface
- GSM/GPRS operating modes
- Power supply
- Power up / down scenarios
- Automatic GPRS Multislot Class change
- Charging control of the GSM part
- Power saving
- Summary of state transitions (except SLEEP mode)
- RTC backup for GSM part of XT55/56
- Serial interfaces of the XT55/56 GSM part
- Audio interfaces
- SIM interface
- Control signals
- GPS application interface
- GSM and GPS antenna interfaces
- Electrical, reliability and radio characteristics
- Mechanics
- Reference approval
- Example applications
- List of parts and accessories
XT55/56 Hardware Interface Description
Confidential / Released
s
XT55/56_hd_v02.06a Page 26 of 125 17.12.2004
3 GSM application interface
The GSM part of the XT55/56 module incorporates several sub-interfaces described in the
following chapters:
• Power supply and charging control (see Chapters 3.2 and 3.3)
• Dual serial GSM interface (see Chapter 3.9)
• Two analog audio interfaces and a digital audio interface (see Chapter 3.10)
• SIM interface (see Chapter 3.11)
Electrical and mechanical characteristics of the board-to-board connector are specified in
Chapter 7.3. Ordering information for mating connectors and cables are included.
3.1 GSM/GPRS operating modes
The table below briefly summarizes the various operating modes referred to in the following
chapters. All information regarding GPS/GPRS operating modes are available in Chapter
4.3.
Table 3: Overview of GSM/GPRS operating modes
Mode Function
GSM / GPRS SLEEP Various powersave modes set with AT+CFUN
command.
Software is active to minimum extent. If the module was
registered to the GSM network in IDLE mode, it is
registered and paging with the BTS in SLEEP mode,
too. Power saving can be chosen at different levels:
The NON-CYCLIC SLEEP mode (AT+CFUN=0)
disables the AT interface. The CYCLIC SLEEP modes
AT+CFUN=5, 6, 7, 8 and 9 alternatively activate and
deactivate the AT interfaces to allow permanent access
to all AT commands.
GSM IDLE Software is active. Once registered to the GSM
network, paging with BTS is carried out. The module is
ready to send and receive.
GSM TALK Connection between two subscribers is in progress.
Power consumption depends on network coverage
individual settings, such as DTX off/on, FR/EFR/HR,
hopping sequences, antenna.
GPRS IDLE Module is ready for GPRS data transfer, but no data is
currently sent or received. Power consumption depends
on network settings and GPRS configuration (e.g.
multislot settings).
Normal operation
GPRS DATA GPRS data transfer in progress. Power consumption
depends on network settings (e.g. power control level),
uplink / downlink data rates and GPRS configuration
(e.g. used multislot settings).