User's Manual
Table Of Contents
- Document history
- Introduction
- Product concept
- Application Interface
- Antenna interface
- Electrical, reliability and radio characteristics
- Mechanics
- Reference Approval
- Design example
- List of parts and accessories

MC55/56 Hardware Interface Description
Confidential / Preliminary
s
MC55/56_hd_v03.00 Page 17 of 104 16.08.2005
2 Product concept
Designed for use on any GSM network in the world, Siemens MC55 is a tri-band GSM/GPRS
engine that works on the three frequencies GSM 900 MHz, GSM 1800 MHz and GSM
1900 MHz. MC56 is a tri-band GSM/GPRS engine that works on the three frequencies GSM
850MHz, GSM 1800 MHz and GSM 1900 MHz. MC55/56 features GPRS multislot class 10
and supports the GPRS coding schemes CS-1, CS-2, CS-3 and CS-4.
To save space on the application platform, MC55/56 comes as an extremely slim and
compact module. This makes it ideally suited for a broad range of mobile computing devices,
and particularly offers easy integration with smart phones, PDAs, and other handhelds.
The tiny MC55/56 module incorporates all you need to create high-performance GSM/GPRS
solutions: baseband processor, power supply ASIC, complete radio frequency circuit
including a power amplifier and antenna interface. The power amplifier is directly fed from the
supply voltage BATT+. A compact “stacked FLASH / SRAM” device stores the MC55/56
software in the flash memory section, and static RAM section provides the additional storage
capacity required by GPRS connectivity.
The physical interface to the cellular application is made through a board-to-board connector.
It consists of 50 pins, required for controlling the unit, transferring data and audio signals and
providing power supply lines.
MC55/56 comprises two serial interfaces (ASC0 and ASC1) giving you maximum flexibility
for easy integration with the Man-Machine Interface (MMI).
An extremely versatile audio concept offers various audio interfaces, each available on the
board-to-board connector: a digital audio interface (DAI) and two analog audio interfaces.
Using AT commands you can easily switch back and forth and select different audio modes.
The external dual-band or triple-band antenna can be connected optionally to a connector on
the top side or to a pad on the bottom side.
The power saving technique minimizes current consumption to as low as 3mA. In SLEEP
mode, MC55/56 is able to wake up on demand and to resume power saving automatically if
no activity is required.
For battery powered applications, MC55/56 features a charging control which can be used to
charge a Li-Ion battery. The charging circuit must be implemented outside the module on the
application platform.