Telit GE864 and GC864
Product Description
80273ST10008A Rev. 3 - 10/02/06
Reproduction forbidden without DAI Telecom written authorization – All Right reserved – Right of modification reserved
page 17 of 72
No service tone;
Alarm tone.
2.12.16 DTMF
tones
The DTMF tones are managed by specific AT commands. These tones are generated with AT
commands only during voice calls. The minimum duration of a DTMF tone is 100 ms.
Group high
Group low
1209 Hz 1336 Hz
1477 Hz
697 Hz
1
2
3
770 Hz
4
5
6
852 Hz
7
8
9
941 Hz
*
0
#
NOTE: The GSM system architecture defines that the audio signal of the DTMF tones is inserted
by the network switches on commands sent by the Mobile Station (MS). Thus, the default duration
parameters may vary from network to network. In case that the devices to be controlled by DTMF
are sensitive related to the duration of the tones and timing of the sequences, dedicated
investigations on the parameter settings have to be made.
2.12.17 Buzzer
output
The General Purpose I/O pin GPIO7 can be configured to output the BUZZER output signal, with
only an external Mosfet/transistor and a diode a Buzzer can be directly driven.
The ringing tone and the other signaling tones can be redirected to this Buzzer output with a
specific AT command.
2.12.18 RF
Transmission
Monitor
As alternate function of the GPIO5, the
GE864
and
GC864
provide the RF transmission monitor.
When the alternate function is activated, the pin of GPIO5 changes to HIGH every time the module
transmits an RF signal and remains HIGH for the duration of the transmission sequence, i.e. it
does not change with every GSM signal burst.
2.13 Logic level specifications
Where not specifically stated, all the interface circuits work at 2.8V CMOS logic levels.
The following table shows the logic level specifications used in the
GE864
and
GC864
interface
circuits:
Absolute Maximum Ratings -Not Functional
Parameter Min
Max
Input level on any
-0.3V
+3.75V
