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 82 of 125 17.12.2004
5.1.2 GSM antenna pad
The antenna can be soldered to the pad, or attached via contact springs. To help you ground
the antenna, XT55/56 comes with a grounding plane located close to the antenna pad. The
positions of both pads can be seen from Figure 50.
When you decide to use the antenna pad take into account that the pad has not been
intended as antenna reference point (ARP) for the Siemens XT55/56 type approval. The
antenna pad is provided only as an alternative option which can be used, for example, if the
recommended Hirose connection does not fit into your antenna design.
Also, consider that according to the GSM recommendations TS 45.005 and TS 51.010-01 a
50 connector is mandatory for type approval measurements. This requires GSM devices
with an integral antenna to be temporarily equipped with a suitable connector or a low loss
RF cable with adapter.
To prevent damage to the module and to obtain long-term solder joint properties you are
advised to maintain the standards of good engineering practice for soldering.
XT55/56 material properties:
XT55/56 PCB: FR4
Antenna pad: Gold plated pad
Suitable cable types:
For direct solder attachment, we suggest to use the following cable types:
• RG316/U 50 Ohm coaxial cable
• 1671A 50 Ohm coaxial cable
Suitable cables are offered, for example, by IMS Connector Systems. For further details and
other cable types please contact http://www.imscs.com
.
5.2 Installing the GPS antenna
In order to receive satellite signals an additional GPS antenna must be connected to the
GPS part of the XT55/56 module. The position of the GPS antenna connector can be found
in Figure 35 and Figure 51. Recommended devices which can be mounted onto the Hirose
connector are available in Chapter 10.
Figure 35: GPS antenna connector (U.FL-R-SMT connector)