User's Manual Part 1

Specifications Expedite G301 OEM Module Specifications 29
P/N 90023363 Revision 1.8
The GPIO’s are not buffered from the host and therefore no voltage may be present on
these lines when the modem is off. The MDM_RDY signal should be used to enable host
side buffers.
Analog to Digital Converter (ADC)
The Expedite provides an Analog to Digital Converter port that can be used to monitor
battery voltage. It can monitor a voltage from 500mV to 6V
Audio Port
The Expedite design provides the connections for a differential microphone and speaker
as well as a buzzer. Testing has shown that for optimal performance, a differential
configuration should be used. This will eliminate common mode noise that inherently
exists in a GSM system especially during the transmit bursts. The microphone circuit
should incorporate an RC low pass filter designed to reduce noise in the 900 MHz and
higher bands.
The buzzer output is a single-ended output with limited drive capability. An external
transistor buffer is suggested to drive the buzzer.
Subscriber Identity Module Support
The Expedite G301 supports a 3.3V SIM as described in ETSI 11.12. The relevant signals
are brought out on the 70 pin connector.
The ETSI specification dictates that the system be made aware if the SIM is disconnected
during operation. This function is handled by the SIM_IN signal. This line should be
asserted high when a SIM is present. The SIM_IN signal is pulled low on the Expedite
module by a 4.7kΩ resistor so that when a SIM is not present the line will be low. Care
should be taken not to use a weak pull-up for the SIM_IN signal. If the module will be
integrated into a system in which the SIM cannot be removed without powering down the
modem, the SIM_IN signal can be tied to the VSIM rail.
Electrostatic Discharge and Electromagnetic
Interference
The modem does not protect itself from ESD. It is the responsibility of the host to ensure
that there will not be any harmful discharges to the modem.
With regard to EMI, the modem will meet FCC part 15 for North American markets, and
ETSI EN 301 489-1 for European markets.