Technical information
Chapter 2: Hardware Interface Description
December 15, 2009 G30 - Module Hardware Description 35
Important: When implementing a single ended loudspeaker design, it is required to place a
series capacitor and resistor on the alert output line, as illustrated in Figure 2-19.
The capacitor should be of low tolerance with values of C = 10-22 uF.
The resistor value should be R = 0
Ω at the design stage, but may be changed to a
different value during audio safety testing, in case that alert level limitation is
required.
Headset Detection
The G30 operates by default in the basic audio mode with the differential speaker (handset) audio
path, for DTMF tones, speech, rings, and alert tones active.
The headset (mono speaker) path is an alternate audio path in basic mode. It is designed for, but
not limited to, a personal hands-free audio device, a headset, using the headset microphone input
device and the headset speaker output device. When this path is selected, the differential speaker
is disabled, and all the audio sounds are passed through to the headset path.
The HDST_INT signal is used to switch between handset and headset audio paths in basic audio
mode. This signal is set high by default at power up. Asserting the HDST_INT signal low enables
the headset audio path and disables the handset path. Setting this signal high will disable the
headset path and enable the handset path.
The G30 supports dynamic switching between the handset and headset audio paths, during
operation and call handling.
Important: The HDST_INT signal does not operate in advanced audio mode. This signal's
functionality is overridden by the AT+MAPATH command settings.
Table 2-12:
Mono Speaker Port Specifications
Parameter Conditions Min Typ Max Unit
Output Volt-
age
No load
Single ended
2.05 V
PP
Gain Programmable in
3 dB steps
-18 0 dB
AC Output
Impedance
32 Ω
DC Voltage 1.8 V
THD 32 Ω load
300 Hz - 4 kHz
1%
Isolation 60 dB