Emc-Relevant Information For Integrators Of The M20; Getting Full-Type Approval With The Application - Siemens M20 Terminal Technical Description

Siemens Information and Communication Products
8.6

EMC-relevant information for integrators of the M20

• Provide for short lines to the SIM card reader (< 150 mm).
• Provide for short lines to the display (< 100 mm) and embed well into the ground (to avoid emitted interference).
• Provide for ground feed lines to the 80-pin connector over a large area to create a screen effect.
• Connect the ground of the terminal's circuit board to a large area on a conductive-material housing, if provided.
• Keep all lines from the 80-pin connector to the peripheral units as short as possible. The maximum length for
supply lines must not exceed 1 m. The maximum length for the I/O lines must not exceed 2 m. If longer lines
are used, additional testing of line interference is needed. Secure the power lines against the ground with capa-
citors at the M20 connector, e.g. 100 nF and 25 pF.
• When laying I/O lines, remove interferences (i.e. if possible avoid parallel cabling to lines from mains supply
or data) or shield I/O lines.
• Provide for large-area and low-impedance connection of M20 housing ground to ground on terminal's circuit
board (screws with spring washers and solder resist release on the mother board).
• Take fine protection (varistor or transorp diode) against overvoltage (transient and surge) into account.
• Audio:
– Use the microphone and handset provided and provide for the suggested connection. If using other micropho-
nes, particular attention should be paid to HF resistance (no HF demodulation).
– Embed audio lines in the ground (to avoid interference).
• Provide for fuses and reverse-connect protection of power.
• Grounded areas on the print whenever possible, prefer star-configuration and avoid circuit-configuration when
contacting these areas together
• Use shielded cable for connection of the display interface pins 1-5, 75-80 when possible
• If a display is connected directly to the print avoid long paths to M20-pins
• Be careful when using #RES (pin 7), it can be influenced easily in ECD-Tests, avoid long distances
• When using the GP-Interface (GPCS/pin29, GPI0/pin50, GPI1/pin51) put resistors 2k2...6k8 serial near M20-
connector in the path
• Using HWR# (pin 6) affords filtering: pin 6 to ground 10pF / pin 6 to circuit 2k2
• CCRST (pin 27) to SIM-reader also needs filtering: pin 27 to SIM-Contact 1k0 / SIM-Contact to Ground 10nF
• CCVCC (pint 52) needs a capacitor 100n to Ground nearby the SIM-Reader
8.7

Getting full-type approval with the application

The Cellular Engine Siemens M20 is a GSM 900 Terminal with external peripherals and is full type approved (FTA) in
two basic configurations. "Configuration" specifies the application and all GSM relevant parts of the application.
In general, new applications based on the M20 need delta-type approval. The delta-type approval process depends on the
deviation between the GSM relevant parts of the new application and those of the already type-approved configurations.
Note: an updated list of already type approved configurations can be ordered from Siemens.
Type approval DeltaFTA for new applications can be carried out by Siemens.
Note: before making an application configuration (SIM card reader, handset, display, etc.) contact your distributer to send
you an updated list of approved components.
8.7.1 Basic configurations with FTA
Configuration I:
– Cellular Engine Siemens M20
– Test Box
– SIM Card Reader Connector L 04, Version: 7434L0425F01, Framatome Connectors
– Handset Siemens Gigaset, Version: 1 (not for sale)
– MMI PC (AT+C Terminal) AT command terminal on PC
Configuration II:
– Cellular Engine Siemens M20
– Cellular Local Loop Phone (CLLP)
Version 8 dated 15.03.00
Application notes
A
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